There are remains beyond the camp perimeter which you can visit although some are a few thousand metres from the main camp. One way you can take a look at these is to jump into one of Jarek 'Sztaba' Sztabiński's reconditioned German military vehicles and let him drive you around the area. Jarek is a retired soldier himself (border guard) and though his English is limited, he's a splendid host who knows the area and what is worth seeking out. You'll find him parked up outside of the hotel at the camp.