If you are going to be driving it - well it first needs to stop (safety), it then needs to steer (safety), and it then needs to go (so you can worry about stopping and steering).
List of what to work on (generally speaking):
1) Brakes
2) Steering
3) Power
After those 'safety' items, then worry about creature comforts like seats, carpet, dash, stereo, body, etc - or do like me and just jump in head first with no regard, that works too!
You can do a lot with $100/mo, you can also get buried and get nothing done. Be careful about what parts you buy. Trollhole (UC member) sells used parts and can hook you up with some of the stuff you need. Many other members have parts they will part with for a reasonable price. Some internet vendors have good prices, some don't.
This might be a good time for a HAMOM. We haven't had one in awhile.
PS - I'm regularly over in your neck of the woods. Shoot me an email at
Steve@SoutheastOverland.com and I'll swing by sometime.