Painting the interior is very difficult when you have wiring and other obstacles in the way. The sooner you can do it, the better. On two of my builds I used a two part urethane type paint over a self-etching primer. On other builds, Iíve used rattle can paint over the self etching primer and I didnít see much difference in either one. Any kind of paint will get chipped off from crawling in and out of the plane. The best one Iíve seen is Hammered rattle can paint from HD or Lowes. The hammered appearance hides imperfections, and when you touch up chips, etc, you canít even see where you fixed it. Keep in mind, if you plan to put in any interior upholstery, much of what you paint will get covered up. If you are going to hire a professional for this, you are going to be hiring him twice. Once for the inside, once more, later, for the outside. And his interior paint probably wont handle the abuse any better than yours.
RV6/2001 built/sold 2005
RV8 Fastback/2008 built/sold 2015