One more vote for the chest freezer. Space versus efficiency, no water to drain, meat not all wet etc., not to mention how expensive ice is, you are way ahead. Have used them for Decades. We debone the meat, put it in cheese cloth, no problem unfreezing it to hang when you get home, then butcher. Truck has a canopy on it, plug the freezer in every night at the motel, it will hold frozen while driving. If you want to marathon drive, put an inverter in tied to the battery. The new trucks all have an inverter outlet in the box already but the barttery won't last long if the truck isn't running so use an outlet at the motel when you stop for the night..