Mark,
You might consider some compartment upgrades before the painting begins. I know one project can become a monster growing out of control, and you may not want to see that happen, but might I suggest:
Moving your wiring and AC hoses into the right rear wheelwell and hiding your taillight wiring in the rear panel spaces.
You will then want to grind off all the brackets that held these items in place, and maybe fill some of the misc. holes in the compartment.
And as for painting, bear in mind if you use the fiberglass tub,it will wear off the paint at the contact points. You might consider contacting owner John Bender at Diamond Liners in Santa Fe Springs, 562-781-1045. His product is a cousin to Line X pickup bed spray (he was involved with it, but kept on upgrading the product on his own). I had it done on 2511 when it was repaired, and it is fantastic. MUCH better than Rhino Lining, and nicer than Line X. A photo cannot do it justice, but it is a 10 out of 10. The pickup bed lining stuff is bullet proof to tools, tub rubbing contact and body flex. And only about $400.
If you think you want to go the Diamond Liner route, call me for some additional pointers.
Larry 559-281-3497 (Fresno)