Given my general philosophy of "make it easy for the player", I put together a barnlike workshop for the armor/chemistry/weaponsmith benches.
Note: In retrospect, I made a silly layout mistake with my build. I put the Player Home, a couple of hand-water-pumps, and the electricity supply next to the workbench shack. I should have put the tool barn in the same area. It *is* the industrial heart of the entire settlement, it should be close together. Everything else is built around the outside. If nothing else, to protect the most important part of the settlement - the tools that made it possible.
Only when the last settler's corpse is cooling on the ground, should any raider or supermutant or whatever be able to get to that area.
So, the toolshed as it were. Start off with some basic concrete blocks, 2 x 3 structure, 6 squares. A set of concrete steps going up. Slab walls. A ratty industrial-like roof. All of the basic structure can be made from vanilla assets, you don't need Sim Settlements or Project Blue Print to do this. They just make it look nicer, a bit more real as it were. Note that there should be a sink to the right of the entrance, for cleanup. You'll see why.
Inside, we have the armor workstation...the chemistry workstation...a cabinet...chemcooler near the chemistry station..old car battery on the floor, just a bit of simple color.
Turn to the right, the weapon workstation. Note the oil slick on the floor. This will be the only area where this makes sense. The barrel is for color, the lantern for when lightning blows half the generators to hell and you have to try and work in the dark to fix things.
Turning to the left, we see a set of shelves on the wall. This is actually quite easy to duplicate, thanks to Worshop Plus and Place Everywhere. You put up the first shelf, duplicate it with Workshop Plus, use Place Everywhere to move it down by 10 or 20 pixels (I forget how much right now), repeat the duplication and shift with the just-duplicated shelf, etc.
So there you have a fully-functional, lore-friendly, convenient toolshed for the use of the player. And the thing looks real too, something that has been used heavily yet also has been as lovingly looked after as possible given the circumstances.
You'll note that there's no Power Armor station. That's in the Player Home - settlers aren't going to be mucking around with that kinda equipment on the regular. Besides, the Sole Survivor doesn't want some blasted settler mucking around with his gear on the random...they'll just blow the circuitry, ya know.
So it's in his Player Home, near the bed and the terminal that's wired into the electrical supply for the settlement.
Hope this is of some worth to y'all. Goodnight.