I don't know a great deal about pre 97 F250's but I have a couple of 'dumb' questions for you:
1) Are you looking at an auto or 5spd?
2) 2wd or 4wd?
If it is a 4wd, beware of any F250 that had a snow plow attached to the front of it. You'll probably be able to pick up a truck like this for cheap, but that's for a reason - the drivetrain will be worn down and the engine weak from the excessive plowing.
I watched my uncle-in-law inspect one the other day. He crawled under the truck and looked over the 4wd mechanism. Looked for any unusual ATF leaks and inspected the locking hubs on either side of the front axle.
BTW, the shocks on those trucks tend to wear out with age.
-Chike