[jocko]

Wheels and tires are such a personal choice that is avoid them unless he’s specifically mentioned a specific size and wheel type.

All depends on your budget. Some options:
New tach n vac instrument cluster from member TBone and/or
Seat cover and carpet if needed
Hidden stereo (if he still happens to have the ol AM in there)
Does he want side trim?
Stock-size Disk brake kit a nice idea - and his current wheels and tires will clear the calipers.
If you do have a good idea what wheels and tires he’d like - I think your size/stagger choice is perfect for that truck - that would be a very nice graduation present!
You’re a good Dad!!