French Door Residential Refrigerator - secure for travel?

Depending on the door handle design just throw a piece of Velcro around the two handles. Having said that the times we have forgotten to do this the doors stay closed.

Re keeping it cool while driving. I am assuming your install will include a proper sized inverter. If so no worrys as the charge line from the truck will be more than adequate to keep the batteries powering the inverter charged up. Residential fridges don't use that much power.