I built a frame for the heat exchanger that has more insulation on the sides and a mounting board for the temperature gauges. The register is temporary–just to have a correct sized opening. I hope to use a thin, decorative wood–maybe ¼-inch. The wood top in the photo is also temporary.
I have insulated the 10-gallon cooler and have to put it back on its base, then shorten the wiring. I will cover the insulated cooler. I am not sure with what yet–maybe wood slats to match the trailer’s front panel.
Note, the portion of the exposed return tubing also has to be insulated.