Basically I built up Sanctuary, Spectacle Island and the DriveIn with a mod that turns off xp for building.  So you have 3 very decent (imo very good) settlements.  Picked up Dogmeat and nothing else.  Level 4 because some critters had to die on the Island.  0 quests done.
The housing built in Sanctuary and the DrivIn is from the Institute set, as it seems to be the only thing we can build that does not get wet inside when it rains.  >.<
The entire settlement in Spectacle Island is over the water.  A- because I thought it was cool.  B- Because I assume that some future DLC will use that island and I don't want my settlement to disappear.
Of note:  After Sanctuary hit ~10 settlers I turned off the recruitment beacon so as to allow space for Preston and crew (should you decide to go that route).  So if you don't want them (or after you get them), the beacon is up on the wall next to the generators.
Lastly.  The idea with the blimps (or as close as I could come to them with existing assets) was one per settlement with a different vendor type on each one.  Sanctuary has the general vendor, the drive in has the armor vendor and Spectacle Island has the weapons vendor.  As you find the NPCs that raise a lvl 3 shop to a level 4, this gives them a pre-built home.
Have fun.  :-)
For anyone that looked at or got my last Savegame (Built Sanctuary and Spectacle Island - Level 4), this is the same deal.  Just *much* further along.  Stupidly so.  To be specific, "stupidly so" is about 60 ours of building.  Still only lvl 4 though.  :-)
Now I'd like to buy a life.  ;-)
Oh!  I was wearing this when I did the save (Slooty Vault Jumpsuit).  So pick it up or be ok with starting nekkid.  ;-)
To make it yours:
1- Load the mods
2- Load the save
3- run "showspecialmenu" at the console.  Set your name and your stats as you want.
4- run "slm 14" at the console.  Make yourself look like you want.  This was my attempt at a vaultmeat toon.  ;-)
5- Save your game.  Then quicksave.  Trust me.
6- Profit.  :-)
The mods you will be wanting to get the full effect of the build are as follows:
Homemaker                                        http://www.nexusmods.com/fallout4/mods/1478/?
Settlement Supplies Expanded 2.5        http://www.nexusmods.com/fallout4/mods/1145/?
Simple Intersection                             http://www.nexusmods.com/fallout4/mods/2683/?
Snap'n Build - Greenhous                     http://www.nexusmods.com/fallout4/mods/4453/?
Snap'n Build - Wooden Window            http://www.nexusmods.com/fallout4/mods/8509/?
Snap'n Build - Metal Window                http://www.nexusmods.com/fallout4/mods/8577/?
Working Food Planters                        http://www.nexusmods.com/fallout4/mods/1490/?
Wattz Powerful Generators                 http://www.nexusmods.com/fallout4/mods/3470/?
Longer Power Lines                            http://www.nexusmods.com/fallout4/mods/2241/?    
Business Settlements (Standalone)      http://www.nexusmods.com/fallout4/mods/6226/?
DDProd AIO HOLY CRAP IT'S ONE ESP   http://www.nexusmods.com/fallout4/mods/8361/?
Bioshock Paintings                              http://www.girlplaysgame.com/wp-content/uploads/Bioshock%20Paintings.zip
Lore Friendly Posters                          http://www.nexusmods.com/fallout4/mods/7145/?
Shack Floors Re-Done 4K                     http://www.nexusmods.com/fallout4/mods/2174/?
Snapshot of the load order is in the included pics.
Not on the list of required mods, but ones I just like and have in:
Crafting Workbenches                               http://www.nexusmods.com/fallout4/mods/2451/?
Armorsmith Extended                                http://www.nexusmods.com/fallout4/mods/2228/?
The new settlers a plus Overhaul vanilla     http://www.nexusmods.com/fallout4/mods/5038/?
Rez's Settler Makeover                              http://www.nexusmods.com/fallout4/mods/8080/? (cause I'm tired of teh ugly - 200+ years and someone had better damn well get a shower going!!!)
And please be sure to drop endorsements on the makers of the mods.  This expression of my obsessive personality would be very different without their work.  ;-)