Hmm. Thinking as a minimalist here:

1. Antiseptic wipes for cleaning off road rash and cuts.

2. Duct tape, which can be used to fashion slings and dressings, and on the trail you use it anyway.

3. Some sort of bandage material.

That's it.

It would be up to the individual to carry his own epi-pen if he had bad bee allergies and such.

Coban would be nice to have if you had room for it. You can get the same at a feeder supply store sold as "vet-wrap".