Helping JimT out with an inframe ...

[tree98]

If you live and drive in the rust belt it will not hold up. Driving through salt here and there is quite different than living in it. Here in the rust belt, the only way to have it last is 1 sandblast 2 epoxy primer 3 Urethane paint or an industrial alkyd like sher-chem (sherwin williams product), but sherchem isn't available in a wide range of colors like a Urethane (imron) or polyester (opticryl) paint. These primers and paints require full respirator and total body covering to avoid contact with VOC's.
I've tried everything under the sun over the years and I'm here to tell you this is the only way to do it if you live in the rust belt. It's a lot more work and requires a lot more equipment but it will hold up.
If you can't or won't buy all the necessary equipment you could just
Google search your area for commercial blasting and painting, then take all your parts off and send them to those guys. Anything else is just wasting time and money.