Hey, I went on a trip, kinda like that when I was in the 7th grade. Our class took a ten day field trip to Crete, my dad was stationed in Germany at the time, which is why we had such a lavish field trip. Anyways, I know its not as long as a 4-6 week trip, but I was able to go and do all my treatments and everything. I carried all of my medicine, and my teachers and chaperones knew about my CF, we DID have a fridgerator in our room, so I was able to keep my Pulmozyme or anything that had to stay cold in there. I did however take a field trip to Amsterdam the next yr, and we stayed in a youth hostel, there, they were able to keep it in a fridge behind the front desk and I would just ask for it when I needed to do my treatment. I kept it in a little cooler, so it was all kept together.
I think that as long as the places where your daughter would be staying have electricity, then there shouldnt really be a problem. Im sure talking to the people in charge of it who are going with her can help. To me, its a once in a lifetime chance to take trips like that, and nothing should be able to keep her from enjoying it. I know I loved all my trips I was able to go on!