Just got a truck!!

You could (should) clean up the rockers and sill panels on the sides that are commonly rusty with a wire wheel and then a 80 grit flapper disc. After that shoot EPOXY primer on it. After that, dupli color kevlar bedliner on both sides. As soon as it warms up I will be doing exactly this, except I have no rust to speak of I'm just thinking preventatively. If there are holes that are pretty big just throw a fiberglass mat behind it, dab a bit of two part epoxy to set it in place while you work and then slather it up in resin, clean it up and finish as above. I had a 89 f150 way way back and thats all I did to it to make it look very presentable. Followed a body crease front to back with roll on bedliner after the prep.