Fixed location is good idea. For example abandoned factory, abandoned scientific laboratory. Many locations like sierra, mariposa, vaults and such would be logical place to find blueprints BUT: they are awful places to pvp. They have grids and elevators without previews that are easy to camp. That needs to go. The maps need to be designed so that players can safely enter them but have a risk of being attacked while inside.
scouts are good enough for that - just make every key location accessible via 2 or even 3 routes and you're pretty much golden.
Buyable blueprints at gun runners for raw cash. Blueprints for sale would be quite random and they would change time to time , let's say 3 blueprint types at a time with a fixed price and amount. Any blueprint could show up for sale , they would cost accordingly to how rare and useful they are ranging from few thousands of caps for some cattle prod BP to 500 k for a combat armor BP.
This is simple but not very interesting, unless those bps spawned in unguarded town shops. Then it'd work like buying cars. Risking big sums of caps in unsafe location which is good.
I like that. Would work pretty much like buying CAs back when they couldn't be crafted.
GunRunners could offer you BPs for sale with rising reputation. The more they like you, the cheaper you get them.
Putting good stuff in safe towns doesn't really provide us with anything interesting to play around with. You run in safe town, get the items you want and get out.
It's not like farming footlockers is more entertaining , i actually can't imagine anything more degrading. So whatever as long as the blueprint distribution is by any means somehow reasonable , feature works don't argue about it. Shop checker alts or not , i bet many people will " check " gun runners for available blueprints , it might actually end up in some sort of interaction but that's not the most important aspect , i just would like to see blueprints available by reasonable means , i'm not asking anything more.
"Bring us some detonator parts from Redding"