Most Helpful Girl
You can get books on edible plants in an area with pictures of them. You could also bring some cord and a fishing hook if there will be stream to fish somewhere nearby.
I have gone off the grid as they say for awhile after a survivalism course. I caught fish and ate mostly local plants. Sometimes its good to have a few trail mix bars in case your blood sugar gets too low. If you have a place to get fresh water that you know is safe you can bring dried beans, rice, and oats. Some tinned food gets quite heavy however you could bring things like jerky, fruit leather, dried fruit and dried fish. They last quite awhile and are quite light.
Lee Valley has stores in Canada and the US. I think they also had a UK outlet. They sell things like a special thermos that you put dried grass or other burnables in one side and water in the main part and it heats/brews drinks. They also sold camp pans and pads, fire starter flint kits, and other things. Though some fishing gear can be got cheap from dollar stores. Make sure you have a good knife on you and multitool ones can be great.
Most Helpful Guy
There are some ways to make food like it that can save it for long time.