I've got a 1980 RRC 2 door. The things I would look out for are rust in the floor, especially in the front footwells and underneath the spare wheel. Also
have a look at the wiring, having been exposed to the heat in the engine compartment for 25 years, the plastic gets very brittle, cracks off and shorts out. Have a good look for leaks on the hydraulics (steering box, brakes, clutch) as these repairs esp on the steering box can be expensive. Backlash on the drivetrain can be a sign of a whole army of problems - I'm going to have to replace all my half-shaft splines to sort mine out. Price of mine was about $3100 at todays exchange rate with about 180 000+ miles on her so your price seems reasonable. And check that your diflock is working !!! esp as you want to use her off-road.
Lot of tech specs at this link :
http://www.rrr.co.uk/Classic/Technical.htm
