i've said before and still maintain i think he was traveling with another group and either missed his connection to leave with them or was otherwise delayed. he had to have had stuff with him (toothbrush, meds, money, change of clothes) just for day to day living. i guess he could have stashed some stuff in a locker somewhere but it still wouldn't explain the lack of any type of daily items (wallet, money, keys). if he had stashed stuff in a locker he would have been trying to get back to it instead of heading many hours south of the concert.
i think a likely scenario is he missed his connection or perhaps the group he was with had to leave for an emergency (lightning strikes at that show btw). maybe he mentioned it to the carolines who said they'd give him a ride if he met them at some location at a certain time. he misses meeting up with them so they leave him a note. he starts to hitchhike, planning to meet up with his original group at some point (maybe another show, maybe he was traveling with a friend or cousin and he's trying to get back to their house to get his stuff).
the only other scenario i can think is someone stole his stuff or robbed him and he was trying to get home.
in any case, no one can survive for long with four quarters, a lighter, and the clothes on their back. he had stuff somewhere and i think that's the key.