Grocery stores and health food stores have a lot of really great entrees that only need to be nuked. We've gotten some very good Indian, Thai, and Chinese food from some of them, and there's always soups and beans and things like that. Of course, a plastic or ceramic bowl will be needed for some of them, but a lot of them come with their own bowl or other kind of container that you can eat out of. I'm remembering right now an Italian pasta with a cheese, tomato and wine sauce that was very good. None of the items I've mentioned needed any refrigeration before they were opened.
You can also get packets of things like cooked brown rice at the health food stores and Trader Joes, which you can top with a can of Thai sauce or something like that. These also do not require refrigeration before opening.
We spent a lot of time traveling around the South last summer and living out of hotel rooms. Eating well in hotel rooms became very important to us.