[Accelo]

I agree with most of the other's advice.
Get it running and safe to drive. Then drive it, daily if you can.
Then work on preserving what you have.
Redo the caulking on the roof, and eliminate as many leaks as you can.
Pull the cowl and clean out the drains on the side. Pull the vents on each side for better access. Spray with a rust inhibitor on everything you can get to.
Clean the rear corners of the cab.

Keep it under cover if you can.

Easy to get burnt out on a large project. Driving it while working on smaller issues helps many finish the project.
Enjoy.