last time I did this it was with a scan tool and a customer with a $38k cheque in his hand. even with photos at hand I still tore a certain black coupe to shreds with paint,belts and undercarrage damage. I think you get the gist. get hte thing UP on a hoist, inspect EVERY inch of it and look at teh seams. also take your favorite fridge magnet with you as you will need it. get a totally UNBIASED report on it. as a marker I know of a car here in brissy (blue coupe) that has the entire passenger side done and externally you wouldnt pick it. I didnt until I did the audio in it and found the cut/pick marks onthe inner shell.
key point - inspect the hell out of it. granted its not a $100k car but its still a deecent whack of $$ to lose.