Upgrading my 72 C-10 (motor, brakes, transmission)

[SCdigger]

I have a '72 C-10. Has the original 250, 3 speed on the column, manual steering, manual brakes, etc. What I'm thinking about, however, is my son will be needing something to drive in a couple years, but for safety reasons, I was thinking about upgrading the brakes, maybe switching over to an automatic transmission, maybe even considering replacing the engine. I've not really ever looked into this in terms of feasibility and/or cost. Any suggestions on making my grandfather's classic an everyday driver for a teen...AND can it be done for $5000 or less (note, I'm not a mechanic!)

Greg