Here's a shortcut tip for creating some of the pieces you might need in your cabinetry.
(Picture shows back side of one mirror image board, and other board mounted on the plywood bulkhead up against the outside wall of the bus.)
Make mirror image boards for trim that goes against the sides of the bus (might work in other identical but opposing locations). I needed some framing for both sides of the bathroom. I wanted 3/4" framing boards that followed the contour of the bus's outer wall. First I cut a 7/8" wide dado in the center of one side of a 2x4 (mine were rough-cut and actually 1 5/8" x 3 1/4" -- odd dimensions). I didn't have a dado blade, so I made several passes on the benchsaw.
Next I made a template of the profile of the outside wall of the bus and transferred that shape to the 2x4, with the bus wall profile on the side of the board WITHOUT the dado.
Then I cut the profile into the board with a sabersaw (jigsaw).
Then I put the board back onto the benchsaw and split it exactly in half.
Voila! Mirror image framing pieces! This would work anywhere you need mirror image pieces. My boards happened to need rabbets (1/2 of a dado), but you could do it with solid boards.
I'm telling you, salvage lumber. You can get it for free, and while it may look like crap on the outside, if you shave off 1/8" it will look brand new on the inside. You end up with some oddly dimensioned lumber this way, but as long as you are consistent with your fabrication and dimensions, that doesn't really matter.