Snacks
Now, for some people, not the most important thing, but for the right crowd this can play a vital role in the epicness of this trip.
Plan for different people, so vary your type of food so everyone can find something they like. Try and keep your snacks ranging from proper foods and different little foods so that you can satisfy your hunger. If you want to make double sure, check in with your friend beforehand to see and make sure what type of foods they like.
Make sure to add a few big fun things:
You are going to do a lot of things on your trip, but try and plan one or two bigger things depending on the length of your getaway.