Quick question on painting … did you use a brush, a roller or a sprayer?
For the cupboards, we removed them and put them on a huge piece of plywood in the basement that had newspapers on it. We sanded them lightly with a fine sandpaper (not coarse), cleaned with TSP and used a good white latex primer by Dulux. We then painted using Cloud White by Benjamin Moore in satin latex. Two coats of the latex, if necessary. Use the best brush quality you can find/afford. The walls were TSPed with this stuff:
… as well but not sanded. You can also just get a good quality white primer and then paint over.
For the walls, we used a small and larger roller and paint brush but first, I TAPED EVERYTHING. Or so it seemed. We did not paint inside the cupboards. If you are a purist, you may want to paint inside but I left them original. If you can set up a spray booth, that would ultimately be the best thing. But we were careful and checked for drips and paintbrush marks.
We replaced all of the handles and door hardware. Measure the holes and get one first to see if it fits. I saved all of the old hardware in a box and put it in the attic in case some day we sell the Airstream and someone wants it.