Thanks for the comments/suggestions/insights, it gives me a lot to contemplate. :) I have used the camper about 4-5 times a year with an average of 4-5 hour drive to the destination. I just installed a new solar panel controller that gives more information about the camper battery status. I'm going on a road trip in a couple of days and will pay attention to the camper battery draw when running the fridge on DC while driving. In the end it may boil down to just run the fridge on propane while driving although I like the idea of using free energy to power the fridge.
PS - thanks for the heads-up about changing my signature; it still shows my old Lance. :)