Correct me if I'm wrong, but he asked for "best" not "cheapest".
My truck is also a driver, but I do not see that as a reason to do a substandard job on it. I do obviously have money constraints so I also used Rustoleum(in quarts). However for a tub of filler, some abrasive paper, and 30 hrs work I can have a
smooth shiny
frame, which is definitely worth it. And now I'm driving it around with a restored frame and rusty body as I am flat out of cash.
