The engel is the way to go in my opinion. I don't take it in and out for it is a bit heavy when loaded. If I do, usually take out the basket, move it, then return the basket.
I often leave the engel in the camper, right under the sliding window. That way, if I stop somewhere I could just reach into the back and grab a drink or so.
If I am with more than 2 people, usually will put the fridge in the back seat of the truck, but am still able to reach it from within the camper if need be.
I also could take it outside and put it under the truck, but rarely do so as it tends to rain a fair amount up here.
I do have power in all those locations, so not a problem. I usually use Anderson powerpole connectors for all electrical, so that is what I have in those locations. I just use an adapter for the cig dohicky to plug the engel into. In the passenger rear of the truck bed I have the outside entension cord. I can run it through the turnbuckle access port for inside use, or use it outside for whatever. Usually, it is for lights under the awning.....
Hope that helps.
Oh yea, I also have a portable solar panel. Amazingly, this will run the engel during mid day by itself. Rarely use it as you've got to position it just right, but when we are stationary for a day or so, it is quite nice.
Good luck.
Dave in SEattle