leaving the parts a safe distance in front of a propane or kerosene jet salamander heater to get them up to 120-140 F for a while works wonders. I think some of the rustoleum tech data sheets have info about temp and time for forced drying. At over 4 bucks a gallon for kero I'm thinking a lot harder about making a solar powered paint drying oven.
I usually spray the insides of my fenders with spray of truck bed coating in a rattle can. Dries rock hard, covers up evidence of any metal work on the bottom side, quiets things down and is easy to touch up.