attaboy, Welcome to the bolt and remember, you eat a big elephant one bite at a time. So it is with these old trucks. Sounds like you have a pretty goog game plan but I'll bet it will change a little as time goes by.
I'm not the body expert here but I think most would say to sand it down and primer it with that tough expoxy paint???
Never the less, build it like a house. Start with the foundation which in this case would be the chassis/brakes and then take it one step at a time. Do a little each day....even just 10 minutes and it will surprise you how it comes along.
Also, if possible take advantage of special deals on stuff as you run into it to save money as you will eventually use it.
And, visit local car shows, and the bolt, regularly for motivation and even more ideas.
Good luck and let us know how we can help. Thanks for saving a piece of Americana!!