That sounds like a plan, no need to do expensive paint on the floor and underside of the cab.
Buy good paint for the exterior, I made the mistake once by painting my 71 D-100 with cheap paint, I had to constantly wax it to keep it shining.
Before you shoot the exterior I would upgrade to a better compressor, something around 3 hp 20 gal tank is enough to spray with.
Make sure it is a belt driven one, the one I am using I bought at tractor supply ~ $350, plumbed and extra 30 gallon tank with it so plenty of reserve to paint with.
Just make sure you plumb in a good water catch.