Paint Booth

For now my main intention is to get the epoxy down. Since the bed is bare metal. Then I can work on rust repair on the cab and also do bodywork on the bed. I am fine with not painting until warmer weather is here. Just need to spray the epoxy and not blow up.

You are headed in the right direction. Epoxy is key for bare metal, the quicker the better. And your filler can be applied right over top, if you need to smooth out any areas. Sounds like you've got a good plan in place.