Once you get your priming done, don't go back to primer. Use more than one top coat with a light
sanding between coats. Since you have all the hardware off, having someone spray it might still be the best bet. If you go that route, make sure that all the sanding is done and that all the taping and paper are where you want it, as the painter will just shoot the trailer. Then you remove all the tape and paper. The best paint jobs are in the prep work, not the final painting
, if the paint is properly applied.