There is a lot of good stuff suggested, and I would add a kit for handling bee stings, tweezers, snakebite kit (Yeah, I know some say don't use them, but get to a hospital quickly, instead. You may be a long way from a medical facility.) Also, a small first aid manual might be useful. Also, bandages to handle sizeable, scrapes and cuts. At this rate, you will need a companion just to carry the first aid kit.
One of the previous posts mentioned mixing pills together in one small container for convenience, but check the law on this. I know in Georgia it is illegal to carry medicines outside of their original containers. As a probation officer, I supervised probation for quite a number of people who did this.