The East Gallatin River near Bozeman is best known for its trout fishing, although that has declined in recent years as a result of development, overgrazing, and increased siltation from suburban runoff.
Because it's flanked by private lands, and is generally too small for other types of boats, the packraft is an ideal mode of travel.
Floater beware: the East Gallatin has its fair share of wood, barbed wire, and bankside willows. It's a twisting stream that at the high flows required for reasonable packrafting (at least 250 cfs), requires fast maneuvering, quick decision making, and a bit of fortitude for wading fast channels above big strainers and sweepers. Rating is PR2 at 300 cfs or less, and PR3 at 400 cfs or more, not because of wave size, but because of maneuvering requirements.
On June 19, 2009, I explored the river on a quick float on the upper river between Bozeman and Belgrade, and used an Alpacka Scout with the Alpacka Ultralight Paddle – a setup with a total weight of only 4.6 lbs.
For a complete expedition, the packrafter can enjoy a remote and rural float all the way from Bozeman to the confluence of the East Gallatin with the Gallatin River near Manhattan, MT. Expect two to three long days, and wait until the river drops to less than 400 cfs so you can bivy on the gravel bars. Respect the Montana Stream Access Law, don't build fires, and enjoy the solitude – the fisherman don't hit the river until flows drop to less than 250 cfs normally.