The previous owners of our unit replaced the RV style fridge with an apartment type 120 VAC only unit. So far it has worked fine for us. Last weeks trip was 5 hours and everything was cold when we arrived at our destination. When boondocking I fire up the Honda EU2000i during the day, and keep ice bags inside during the night. The freezer in this thing is unbelievable
While a 120 VAC fridge might not be for everyone, it works for us and they are only around $300 at HD or Lowes.
BTW, we added velcro strips to keep the doors shut during transit.