HELP! Whadda I do next!?!

[krue]

This 70 GMC swb stepside is my first project. I plan on using my truck like a truck. I know enough to do the mechanical stuff, but I don't know jack about body work.

I know I need rocker panels. But what do I do about surface rust to prevent it from rusting thru. For instance on the box for my stepside bed there is some surface rust where toolboxes used to be. How do I fix it until I can afford to get it painted. Also on the front right fender at the front bottom corner it is rusted through. Can I fix that or do I need to find a new fender.

Any ideas will be greatly appreciated!