There is also AppImage Launcher which works nicely for me. It automatically integrates AppImages into the DE (e.g. search and start menu) and a few other nice things.
I'm not sure what "walk around a lot" means exactly but I've interpreted it as hiking and I'm fairly certain that you will have a very bad time when hiking for three days without ANY food.
And why do you think that you won't be able to consume enough calories without food? All kinds of drinks should have enough energy to sustain you, e.g. soft drinks, especially if you sweat and therefore drink more than 2l a day. In the worst case you can also just eat sugar.