Even 200mm might do. Elsewhere, as in Africa, bring the longest lens you have and a teleconverter. The new carbon fiber tripods are lightweight, but very costly. For film, Velvia is a favorite, but often, at ASA 50, too slow. We find that 100 ASA is good, and can be pushed to 200 with little or no loss of quality.
Most people figure on using between five and ten rolls per shooting day.
Most airlines are very strict about carry-ons, especially in economy class. You may be forced to check items you would rather carry. Do not check the film. The new CTX 5000 scanners used on checked bags can utterly destroy your film and make your trip a total loss. We suggest you put all film in clear canisters and then in clear Ziploc bags and ask for hand checking at the gate.