Hi Tom. Hopefully when your wife sees the final project, you'll get the green light!
I have machine sanded the second coat of epoxy, and now I have to hand sand all the corners. I had filleted them all with epoxy, so the sanding consists of wrapping sandpaper around a small, deep well socket (12 mm or so) and just rubbing it back and forth along the fillets. I have also filled in some voids with more epoxy and filler.
I made a small design change. The Coleman thermoelectric refrigerator was not going to work well for this application. First, its a power hog, so we would have to carry the food in a cooler to the campsite, or else run 12V from the tow vehicle back to the camper. It has an inlet and an outlet on top of the cooler, and under the cabinet, after it ran for a while, it was just circulating hot air and not cooling anything. I experimented with some ducting to keep the intake and the outlet apart. This worked, but it blew hot air into the camper--something else I didn't want. I decided to go old school and install a Formco Ice Box. As luck would have it, the framed opening I built is the perfect width for this cooler, and slightly taller, so I can fill that in easily.

The reviews suggest that by itself, it doesn't hold ice all that well, but if you install blue foam around it, it will work very well. It should arrive next week, and it should be a simple matter to get it installed.
I'm hoping to do the third coat of epoxy on Saturday.