re: Lewis and Harks Montana Exp of 2012
We have enjoyed DIY trips to MT/WY for 20 years now. Each trip creates lifetime memories, but don't discount the "before trip" research, map review, book reading, forum postings and pre-planning it is and can be a tremendous amount of fun. Enjoy the anticipation during the next year, then when you actually go, stay open minded and keep the only expectation one of "being there".
Anyway, as others have posted, more water than can be fished in a lifetime. My suggestion is to make a tenative plan, then have a secondary back up plan. It is important to have some flexiblity in your agenda on a DIY trip. You can never predict when an area you planned on visiting is closed for access. We have had trailhead, river access denied because of grizzlies, forest fire, high water temps, and road closures due to rockslides etc etc.