This is now the 4th settlement I've decided to upload.  If you like this one and haven't seen the others here are their links:
Starlight Drive In Trading Hub And Settlement
Nordhagen Beach - A Tough Thriving Community
Taffington Boathouse - The Commonwealth's Water Provider

This settlement blueprint contains over 1,200 objects. I experience no lag. 

With this settlement I really wanted to convert this sewage plant location into a bustling market center. I kept it mostly lore friendly and packed it with everything I could to give it that sense of abundance and prosperity. I also really wanted to tackle the Roger Warwick story which I never felt quite satisfied with in the game. We learn from the institute terminal in the food science division the exact details of the experiment and plans for the location. However what we know to be true and what we are presented with in the game just seems disconnected.  To fix that I added a secret Institute outpost to the settlement. Pretty easy to find but hey we path better than NPCs :)

I know my Decorations section of mods is fairly extensive. I do recommend having all of them in your load order to get the full effect. The structure related ones are needed to have everything built correctly. 

I do love all the mods that are listed. They really give the variety of choices needed to make something like this. I don't have issues or conflicts with them. But I do manually override Loot's load order by making sure that all Workshop Rearranged related entries are below all other workshop mods.

Steps to get the full effect of this Settlement.
1) Get the mods needed
2) If the area hasn't been cleared of the original assets - then clear all the big stuff. You  may end up with duplicated objects after the transfer, but it shouldn't be a problem.
3) Important: When you use the Transfer Settlement Holotape import function make sure that you check the box for Import Original Items (not built by player). If you don't do this then any original items I moved will not end up where I moved them to.
4) Note that my taste in "artwork" is personal choice. You certainly don't need the related mod. The ones you may see in the images are replacers so without the same mod setup the same way you'll just have whatever your equivalent pictures are.


Absolutely Necessary Mods


F4SE (This is an off-site link)
Transfer Settlements
HUDFr

I personally use the SKE framework for several of the mods below that support it. Sorry but I am no expert in helping setting these up. 


Necessary Structure Mods

Alternate Settlements  Grab both versions 1.1 + 1.2
Buildable Barricades and Guard Posts
Buildable Burning Campfires and Fireplaces
Office and Store Buildings
Passive Water Resources 
Place Everywhere
Scrap Everything
Settlement Objects Expansion 
Settlement Supplies Expanded
Snap'n Build
Snappy HouseKit I'd recommend grabbing the DLC stuff for this one. Awesome mod. Takes a bit to figure out how to use some of it but worth it!
Starlight Drive-In And Diner - Lighting - Original v2.0
The Kuro Tab The Structure pieces in this mod are Epic! Be careful with some of the decoration pieces. I have a hard time deleting a few of them (no problem ones were used in the settlement)
Thematic and Practical
Water Sources Expanded 
Workshop Rearranged Make sure that you also grab the Workshop Rearranged Patch Pack


Recommended Decorative Mods

Adult magazine billboard and posters (personal taste)
Advanced Workshop Food Harvesting
Armor and Weapons Keywords Community Resource
Atom Bomb Pinups Paintings (personal taste)
Better Ammo Boxes
BetterStores GER (I have the German version cos the English one was under review - now I see the German one is too so if you don't have this already you'll loose a couple of posters and a butcher counter in the market) 
CREAtive ClutterCrimsomrider's Unique Furniture DLC Edition (read mod to see which if any patch you might need)
CWSS Redux v2 Craftable Working Showers Sinks Baths Toilets
Dino's Decorations
Do It Yourshelf
Eow Pre-War Books Retexture
Gruffydd's Signs and Posters
Gruffydd's Signs of the Times
Illuminated Billboards - Lighting - z All In One
Immersive Vendors300-EN
Just some Curtains and Rods v2 & v2a
OCDecorator - Static Loot
Old World Plaids
Pictures Of Remembrance
Radio Model Replacer
Retextured Chems
Retextured First Aid Kits
Settlement Markers
Signs of the Times - Posters - SotTP 1.3
Vending Machines -Lighting - Main
Working Table Lamps
Workshop Decorations Pack

Finally I just want to say a huge thank you to all of the authors of the mods I'm using. Thank you for your hard work. Thank you for providing new and inspiring ways to extend the life of a great game.  Your creativity inspires me.  I'm running around 180 mods - many of course not needed for this - and love what each of them brings to the experience.