MAke him a $5,000 offer and see where it goes.
You can figure that the tires are probably 10 - 12 years old? The tires are not safe for a long high speed drive. Keep it under 55 MPH. Keep the tires at 80 PSI (or the recommended high pressure limit). Do not load up the camper or do any camping until you get new tires. Be ready for a blowout - it can happen with tires that old.
You might need a front transmission seal. You might need a rear axle seal, or brake pistons rebuild due more to it not being used much. Probably the brake fluid is bad, and should be changed out.
Good luck!
Fred.