Trail Cooking

For the hash browns you can find a couple types in grocery stores, often hidden with mashed potatoes so look if you don't see them. The brand I used had salt added, taste before salting. You can also dry frozen hashbrowns at home and use those.
For the cheese, use either shelf stable cheddar or the real cheddar, depending on how long you will be gone - or how hot it is.
Dried celery flakes can be used, find those in the spice section of grocery stores.