Wild suggestion/idea: If you wanted to make a more 'OP'/'late-game' bunker that acts as the ultimate player safehouse but didn't want it to be too accessible in the early game as it'd be game-breakingly easy for the player then you could utilise a system like in the 'Echo Station' mod.

Within that mod, you're able to take an elevator down within the military base to an 'underground' level (it actually just spawns a player onto another level, I believe). Theoretically, you could use a similar system for the bunker + tie it in with a very rare 'access keycard' only to activate the elevator (which I believe may have been done with another mod?).

Just spit balling an idea.

I second this, my only other suggestion is a more remote location surrounded by a chain link fence and modeled sort of after the Day of the Dead(1985) Shelter

My suggestion:

Make a second version of this mod, with the bunker being at a different, specific location.
I made a POI at PZ Maps, showing the location.
It would be cool if it would be still enclosed by trees and if it is connected to the road.

I would highly appreciate if you could do that, as I find that building / basing there is pretty nice. I hope that this is possible to make as it would mean a lot to me!
Thank you in advance!

https://map.projectzomboid.com/#0.4113522435304772,0.19982724139921687,59.53741807651281

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Update:

I have found a location I would prefer more.
It is in Ekron/Licksillet.
It would be cool if you could replace the following house with the bunker, or you make this house as a bunker with grass platform and such.
Of course connected to the road, and if possible, surrounded by trees.
And once again, thank you in advance! It would be soooo cool!

https://map.projectzomboid.com/#0.38917479864307725,0.15883527424582736,256.0000000000003