Your questions are a little to vague to answer. But, like buying any used truck, you need to take a close look at everything to make sure everything is working as it should. I don't believe there is anything on the truck that cain't be repaired or replaced to keep it in service.
I would change all fluids, lube all the grease points. Get it up on a lift and check all wear points like ball joints. Replace worn parts. Run a compression check and monitor oil usage on engine.
Keeping it orginial as possible will make it easier to sell when the time comes.
Questions on the different sections of the truck can be addressed in the shop section of this forum. The guys here have "been there, done that" and will be glad to help.
Welcome and good luck with your truck.

Six volt guy living in a twelve volt world