The ruins are in a forest and Wolf's Lair was a sizeable operation complete with casino and cinema as well as more 'operational' type facilities.
It's an interesting place to visit. Also, you pay a set parking fee on arrival (about €2.50) and then you can stay as long as you want, even overnight. So, many motorhomes, caravans, and tent travellers do stay (there's even free electricity, toilets and showers). Staying overnight gives you 'extra hours' access to the site: because you are camped just there, onsite. So, in the morning I took a morning walk around the Wolf's Lair: alone!, without any other tourists. Wolf's Lair takes on a whole new 'air' when you're alone, and that is that it feels extremely sinister! It really gave me a creepy feeling.
Note: take a flashlight if you visit.