I am not good at being brief, obviously, so strap in for what this mod does.

This mod is not a "Redux" or a replacement. It is an expansion of Ethreon's Red Rocket Reborn.
Red Rocket Reborn is one of my favorite, and must-have mods for Fallout 4, however being somewhat compulsive about certain things, I found myself expanding on their original mod, initially for just myself, but in the end, and with Ethreon's permission, in a more substantial way. The original mod is required for this to work. You will also need to run their mod, Master Plan.

This is a list of things added to, and changed by, my mod;
Note: all new meshes have full, custom collisions

Update 23/07:

Added to the main file:

• Fixed the interior pillars so they are entirely visible and don't clip through the ceiling.
• Added a second Armor Workbench replacing the bellows with a Mr. Handy and shifting the clutter around to be more visible.
• Added SHK interior ceiling and exterior foundation trims. It's the little things that add depth.
  

New File:
Snappy HouseKit Red Rocket Expansion
With robboten's permission, I have added a SHK Red Rocket expansion set. It is not major, but it may add some cool pieces people might enjoy. The following have been added to the appropriate categories of the Red Rocket kit in SHK:

• New RR foundation set, added to the concrete floor category. Uses the same textures Ethreon used for their shell foundation, but in handy SHK floor varieties, including a new quarter curved corner.
• Standalone RR foundation trims to be used with the new foundation floors. See the screenshots for reference.
• Additional ceiling pieces added to the base RR floor. Empty light sockets so you can inset your own lamps, as the base SHK light floors are not super bright. Includes standard, corners with the socket facing both directions, and half. Extra bonus, a quarter corner floor/ceiling!
• A SHK standard wall with the main menu garage windows built in!
• Final extra: In the concrete base walls, there are 2 new curved base walls, a full curve, and a quarter curve, that match the curved corner floors of the ShellKit and the RR kit.
  

All new elements have full snap points and collision!
Obviously this file requires SHK to function.

The Fun Stuff

• Added: A standalone Mr. Handy Corpse. The mesh has also been fixed as Bethesda was very lazy with texturing it and half the textures didn't line up properly.
  

• Added: Pump accessories for the long sloped roof. This is my personal preference for the overhead pumps, as well as the large dome under the rocket, and the silvery hubcap things on the curb. I know these pieces are loathed by most, but I like them for flavor. This was a gas station after all. It has a snap point, but it doesn't work for some reason. Simply match its coordinates to the long sloped roof and it should be perfectly placed.
  

• Added: Armor Workbench with the same clutter as the worktable with the pip boy. This functions as a normal armor workbench. Unfortunately there is no way to include the Mr. Handy in the mesh that I was satisfied with, which is how the standalone Mr. Handy came about. I may tackle this further in the future, to get the Mr. Handy and Armor Workbench to play nice and look correct.
  

•  Added: Variation of the long sloped roof to use the tidied siding from VIitS mod, Repaired Red Rocket, included with permission. This roof, unlike the base roof from RRReborn, is adjusted somewhat to play better with SHK Red Rocket roofs. It has the same snap points, but there was a gap when using the original roof, and while it still works great with the other shell options in RRReborn, it didn't work well on its own. The added roof will work great with Snappy House Kit, with zero gaps or overlap.
  

• Added: A variation of the pip boy work table was added with the clutter adjusted to make room for a ham radio. Or anything else you might want to put there.
  

• Fixed: The pip boy work table got updated and given increased fidelity to the main menu table. The Mr. Handy was replaced with the updated mesh I did. I also added the 3 fusion cores, and shifted the clutter around both in position and scale to closer match the table in the main menu. Additionally I fixed the broken textures on the pip boy and increased its scale to match both the scale of it in game, as well as how large it looks in the main menu.
  

• Fixed: Normals for all the tools on the two tool racks have been dealt with, smoothing out all the faceted edges.
  

• Fixed: Some of the laser rifle mods were missing in the original mod, and lacked pegs to hold them up. All laser rifle mods are now present, and properly pegged. Give or take a peg hole or two, this board now matches the main menu perfectly.
  

• Fixed: Issues with the cloth over the mini-gun by the dresser. Clipping back faces and broken normals all sorted. I also adjusted the UV map a bit to make the cloth more detailed, and aligned a hole in the cloth with one of the mini-gun handles. Additionally I adjusted the ammo box snap point so that the inner one no longer clips with the dresser.
  

• Fixed: The tools and clutter around the Power Armor station were a bit too spread out for my taste, and there was one hammer which was way too close to one foot. I adjusted the positions of the clutter items accordingly.
  

• Changed: All interactable objects have had the "RR - " Prefix removed. This was a pet peeve of mine, but I stand by the edit. 
  

The Big One
A new "shell" has been added. This shell is designed to be essentially a façade. Instead of the main menu garage being an entire building, it is a piece that can be added to an existing structure. There are 2 versions, one with the brick textures from the main menu, the other using the same brick texture as vanilla Red Rocket garages.
The façade is decorated with the pipe, the posters, the chains, the clock, and the nuka chimes from the Decorated Shell, but otherwise has none of the other decoration options built in. It does however have all the snap points of the Basic Shell which will let you decorate it however you like.
The façade has a snap point on the same wall as the windows of the garage which is aligned perfectly to the Red Rocket tile set from Snappy House Kit. The dimensions of the garage were also adjusted slightly (read: not noticeably) to perfectly match lengths and widths of the Red Rocket tile set, making it super easy to build a structure around the garage using that set.

Caveats and Notes:

• As is probably clear, this façade was designed specifically for Snappy House Kit's Red Rocket set. Like, vehemently designed for it. You are of course welcome to experiment, but please keep in mind I did not design this for maximum compatibility, I designed it to be used in conjunction with SHK only. You have been warned.
  

• The Power Armor Station snap point is there, but it doesn't like to work. I cannot figure out why
  

• The SHK snap point is only on the one wall, you will have to circle the walls around to match up with the other side of the garage façade.
  

• There is a hole on the right hand corner of the façade, the corner that has no snap point. This is because it fits a plain curved wall from the Red Rocket SHK set perfectly. This is the connection point when you loop back around, and unfortunately there is no neat way to have that work standalone. If it is requested, I can upload a version where that wall has no hole, but the connection to SHK pieces would be deeply flawed.
  

• Due to the garage itself not conforming to the standard sizes, I did construct the floor/ceiling for it. On its own, it is a bit odd, outside of the main garage, but it is designed to fit perfectly to SHK shell kit pieces. As such, once it is set into a larger building made with SHK elements, the floor and ceiling should be seamless. There is a very tiny and bizarre seam visible on the ceiling. It is not major but I have no ideas what is causing it. The textures I chose are the default textures. If you want them to match other textures, you will have to edit them in nifskope manually.
  

• For the ceiling, I opted for the empty light fixtures. If there is some sort of outcry for a smooth ceiling, I could put something together.
  

• I made the totally broken window intact. I left the window with the bullet hole alone, as it adds flavor. The fully shattered window bothered me.
  

• Finally, I was forced to adjust the height of the narrow doorway. As such, I added an additional version of the door that will match the height of the façade doorway.
  

The Optional File
This is an edited garage door that will replace the Red Rocket garage doors throughout the game. I am very clever about mesh editing, but animation has always baffled me. I edited the animations for the door frame by frame in Nifskope, but to be honest, I did a real bad job. 
The garage door absolutely works, as long as it is set to 1.35 scale. When it is not set to 1.35 scale, the collision misbehaves and only goes away while the door is opening or closing. When the door is opened or closed, the collision acts like it is closed. 
If anyone has any notions about this, please let me know. 
If you download this, be aware the door has no snap points. You will need to set the scale to 1.35 and position it manually either with Place Everywhere or the console. Or both. I do NOT recommend using this replacer. However when scaled and placed properly, it works gorgeously with the main menu garage.
That being said, the button that controls the door, as well as the "wires" all need to be shifted manually or with Place Everywhere as well, as the button does not line up with the façade or the original shells.


Notes

• Red Rocket Reborn and Master Plan are required for this mod to work. All new additions can be found in the appropriate category of the Master Plan sub section. I did not go through material costs with a fine tooth comb. The attention to detail on that done by Ethreon was a bit beyond the scope of what I am doing here. Initially I simply replaced the meshes when just using it for myself, but when compiling it all into a proper mod, it seemed prudent to make new things constructible and aside from the aforementioned altered pieces, leaving Ethreon's work alone.
  

• There is a small amount of DIY to this expansion. I tried to make the necessary snap point edits (for example, the new Armor Workbench snaps perfectly into the garage, albeit in a slightly different location to the original pip boy work table) but snap points baffle me somewhat and I find them frustrating, so I didn't kill myself over them. If you want to change the floor/ceiling/brick textures, you will have to do it yourself, though the UV mapping is such that there should be very little trouble with swapping to another tiled texture.
  

• Everything does have accurate, custom collision meshes though, which helps.
  

One Final note, and then I promise, it is over.
I took the screenshots of the façade before I went back and made major changes to make it more user friendly. Initially it required a LOT of maneuvering to be useful, but every time I wrote an explanation about dealing with how useless the mesh was on its own, I was overcome with rage and I went into 3ds and fixed it. 4 iterations later the product included with this mod is the result. it is functionally seamless to add it to a SHK Red Rocket building, requiring zero effort and offering a maximum of compatibility. With SHK. With anything else and I have no clue. There should be some compatibility, but obviously it won't be as quick or easy.
The Red Rocket in the screenshots is my personal HQ. I am showing it to demonstrate how the façade can be easily worked into a larger building and look quite natural. The whole purpose was to let folks have a bit more fun with the main menu garage and to increase fidelity of the individual elements.

Please feel free to post screenshots of what you all build! I would love to see how folks find a use for all this ^_^