My SO and I are looking to take a week or so to travel this summer somewhere (anywhere) in the US. We're hoping to find a beautiful place to camp close to good swimming (river, lake, etc). We live in Oregon currently, but are willing to drive for up to 10 hrs or take a plane. We've been thinking about going to Glacier, but want to be somewhere that isn't too crowded during the peak months. So we're guessing most National Parks are out of the picture. Any suggestions? Specifics would be great.
Edit: Also, we're pretty low-budget. We don't want to spend more than $300 round trip on airfare and would like to camp or stay at hostels for the week.