Our family is going to Glacier National Park from August 6 through the 15th. We have two sons who are 23 years old and 20 years old. We're flying into Kalispell, and plan to be on the southwest/west side of the park for the five days that our oldest son is with us.We've never been to Glacier before and have never been white water rafting, although all of us are good swimmers;-) Can you recommend a good company to go through in order to make reservations for white water rafting? And about how far in advance should we make the reservations? Thanks!