I've been to all the places you're hoping to go to, albeit in the last 10 years or so. I'd highly recommend bringing all the film you think you'll need, even back in 2001 (Cambodia) the only film available was consumer-grade negative film that had been baked in the sun. You're F2S set-up is very similar to the one I tend to take when travelling when I want a range of focal lengths but also as light a rig as possible. You don't say how long you are travelling for or the focus of your trip but I'd budget at least one film per camera per day (x different film stocks) for the trip (although you'll probably go through a lot more while at Angkor Wat). Are you mostly a black and white shooter or a colour one? That might also influence how much you bring of each film. Definitely go with the film stock you are most comfortable with. Tri-X is great because you can pull it a bit for real sunny shots and push it for low light temple shots. Be aware thought that in some of the temples you may want a flash to help you out a bit.