I like open face grilled cheese sandwiches in the toaster oven. Toast the bread on one side, turn over and remove from oven long enough to put thick slices of cheese on top, then heat until cheese is melted and a little runny. MMMM! And I don't even eat dairy much any more.

I think an electric skillet is more efficient than a toaster oven. And you can get compact microwaves that would go along for the trip. I personally prefer to use a portable convection oven--they're more versatile than any of the other devices listed.

SRS