You're going to have a pretty hard time finding abandoned and secluded realestate here in W. Germany. That's not saying there is none, but it's more of a "if you know, you know" thing. There are a few abandoned and run down farm houses and barns in my area, but they are right next to Landstraßen, so you'd be seen pretty quickly by hunters/farmers/passersby.
There's still unfound bunkers around Nürnberg to be discovered, but that's not something you want to do in full Stalker gear, and from what I understand most of the ones that are found have been previously blown or are flooded from groundwater.
Your best bet is really to just go to E. Germany. It's much more sparsely populated and there is a lot of old Soviet stuff still around, like old bases, bunkers, and tons of old villas. I drive around Thüringen a lot and there are tons of old buildings and factories to see. A really nice place to look around is a town called Katzhütte. On the way there coming up from the South there are tones of tiny abandoned steel mills and the like. If you were to park in a town and hike in I'm pretty sure you could spend a night in one of them if you're being discreet.
Anyway, here are some likes that I've collected, maybe this'll help.
https://de.wikipedia.org/wiki/Einheitskraftwerkhttps://www.urbex.nl/map/https://www.sightraider.com/https://innazone.neocities.org/ 