I spent a couple of hours today with Richard Parks of the Park’s Fly Shop in Gardiner, Montana doing some Wikipedia research. As an aside, Richard and I talked about his prognosis for the upcoming season. Snowpacks are close to normal in most areas, and baring any late May/early June cold spells and storms, Richard believes this year will be a good one in the park–for two reasons 1) pressure will be down because of the economy and 2) waters levels and temps should be normal. Addtionally, this year’s NPS road program is going to impact fishing (positively or negatively depending on how you see it).
In August, the NPS is going to close the Norris to Madison Junction Rd for the remainder of the season. This seriously impacts access to the Northeast corner (Lamar, Slough, Yellowstone River) from the West Side and vice versa for the Madison/Firehole from the Northern entrance. Richard has a lot more detail posted at: http://www.parksflyshop.com/roadwork.htm. If you are planning a trip to the park this season and want to fish a variety of areas, this road closure needs to be factored in.
After my interview with Richard, I took a quick hike up the Rescue creek trail to the top of Rattlesnake Butte in the park to see what the Yellowstone was up to.
This is the Yellowstone just south of Gardiner. This very accessible water recieves little pressure, especially in the Fall when its in its prime. About a 1 mile walk from the trailhead gets you access to about 2 miles of really nice water just south of Gardiner.

River looking south from Rattlesnake Butte