as far as running parts go these guys have the list down...bring a jack to check the front end, do a good shake down. check the track bar and its bushing and heim joint boot for rips and slack. Steering boxes get sloppy after plowing or high miles. check the tranny fluid for a burnt smell or a color other than blood red. rub a little fluid between your fingers. if it feels gritty step back and thank the guy for his time.
as far as the bodys go on these trucks, check the rocker from the inside of the door jamb for rot. also check the front and rear fenders for bubbling and rot. other than that enourmous list of things to look for...lol should be okay!
p.s. just picked my 99 up for 6 grand with 90k on it. needed a lift pump and some front end parts. body is a lil rough but nothing too extreme :~) congrats on the good find