A point worth mentioning about onboard refrigerators.... 
Conventional van fridges have a door at the front, hinged along the side.  Every time the door is opened, all of the cold air is dumped in seconds and is replaced by the surrounding air.  If it is 45 inside the van, that's what goes into the fridge.
Chest refrigerators, of the Engel variety, have a top lid.  When the top lid is opened, there is no automatic spill of all the cold air.  The difference this makes to keeping the contents cold is very noticeable. 
The top hinging lid means that it can't be built into a convenient cupboard but the improved performance more than cancels that out.  I strap mine to the floor, using a couple of cleats in the floor and a couple of turnbuckles.  This might sound like an overkill but the last thing you want flying around inside is a fridge full of food - or beer, in the case of some of our members.