A buddy of mine just purchased a 2001 27ft Fleetwood wilderness with a slide for $1500. He took a gamble we were not sure if anything worked. it was full of trash and had no way of testing anything. In a way he was glad he didn't. The owner would have probably tried to jack up the price a little bit he had a take it or leave it attitude. It had been sitting in a tow yard for 3 yrs and was dirty! We got it back to his place we threw in a couple 6v costco batteries and it came to life. Everything worked perfect. Only thing it was missing was the LP Fridge. It had a regular compressor fridge. Long story short my buddy is very happy with his purchase. He had to invest a lot of time in cleaning, installed a new floor and blinds but thats about it.
There are some diamonds out there if your patient and have knowledge of appliances structure and roofs. My suggestion to you would be read a lot on the forum. The people on here are very knowledgeable, friendly and always helpful.