Ram,
Welcome!
I did the same thing in our first tt. Mounted a 4cu ft, 2 door dorm/apartment fridge. Worked of great, even on trips that took about 3 hrs to get there (stopping for breakfast/restroom). Only thing I will suggest if you didn't is to consider sealing around the fridge to keep the warm air from coming into the living area.
I will try to find pics from when I mounted ours. I used 1/2" (or so) plywood, screwed into the wood border. I then screwed (maybe 1" or 1.5") strips of plywood on the inside of the plywood filler, sandwiching a garage door seal between them, with the angled part toward the fridge, angled toward the living area. When I slid the fridge in, it bent the seal back againstt it's natural "angle", keeping a pretty good deal against the fridge. I also mounted a small 110v fan (one that rotates 180*) behind the fridge pointing up. Only used the fan on warmer days. Everything worked as planned!!!
Also get a childproof fridge lock for when traveling. Don't want stuff falling out. We have used the one that sticks on the side of the fridge and has a vinyl strap that goes around the corner to the door, sliding into the base.
Hope it all works great for you!