I own a 99 5 spd and here are my ideas...
Agree with others on the front end is a big problem with the heavy engine over the axle.
exhaust system, see if it has been redone; SS exhaust is best.
Tires, don't minimize this as a good set is ~ $1000 for 4 E rated tires.
Cruise controls have chronic problems on this vintage, usually a vacuum leak.
Ditto foglights--need to replace the headlight switch to get them to work; about $150 to r&r.
Ask if the rear axle ABS sensor has been replaced, not a big deal, but another $100 to do so.
Rear Axle seals; they tend to go out, dump lube on the rear brake shoes and essentially leave you with two wheel braking--about $200.
Check A/C heat exchanger (near radiator) to make sure its clean--if not, you will not get much cooling in summer, and run HVAC fan to make sure you get good airflow on all speeds; if not you are going to have to clean the system under the dash.
Windshields are CHEAP, ~ $200, installed.
Here is a used car checklist [generic] that is a good idea to use, so you don't "fall in love" with the truck prior to inspection.
AIS Used-Car Pre-Purchase Checklist - MSN Autos
Lastly, IMHO, these trucks have crappy (thin) paint. Use the checklist to perform inspection.