It's all over the thread the other member posted, but off the top of my head:
V8: Timing Belt/WP around 90-100k interval
Refreshed V6: Oil leaks around timing covers
Valve cover oil leaks
All 4wd modes engage/disengage
Frame rot
Dash and HVAC lights all functioning
If Xreas, look for leaks
Torn CV boots + suspension bushings
Seized calipers
Maintenance history for plugs, oil and fluids, diffs + transfer case, ATF
Register and run the VIN on any Toyota thru the owner's club to get any dealer services details.
4th Gens are all nearing 10+ yrs or older now. There will be some stuff wrong, but most are DIYable.