I'm gunna interpret your choice of the term "excursion" to mean that you'll be riding rather than hauling and you intend to be self-sufficient. If that's the case I'll give you my four top priorities:
#1. Fuel capacity. In a tank. Between your legs. Not taking up gear space in soda bottles, gas cans, old hot water bottles, tool tubes, Kolpins, Rotopaxes or any other vessel which by its volume, shape or attendant bracketry reduces space for said gear or puts weight where it doesn't belong.
#2. See #1.
#3. A BEEG rack. Beeger the better.
#4. A bike which fits you.
#5-10: Probably about the same as everyone else.