What's your goal going into the trip, and what's your goal coming out of the trip? In other words, what's more important: having good pictures, or having a lens owned by you when you finish the trip? I say that to prompt you to consider renting. You may want to rent the next lens you think you might buy, or a lens (or a few) you won't buy anytime in the next 10 years (or more) but will make a difference in your photography on this trip. (I'd consider the EF-S 10-22 and either the 70-200/4IS or the 85/1.2, depending on whether you expect more action or portrait photography.)