Originally Posted by mtdave
If it was me, I would head through Red lodge, over the Beartooth Highway to Cooke City and fish in the park. Then fish the Yellowstone to Livingston and get back on I 90. This may take more than 2 days though. If you miss the turn off and end up in Cody you could fish the Shoshone and enter the park from the east and then fish your way to Jackson where you will have to fish the Snake towards the west and then your not that far from the Henrys Fork.....which is still on the way to the Missouri...... or fish both Boulder rivers, the one south of Big Timber and the next day farther west out of Boulder, Mt. It will be a great trip.
Just fyi, Beartooth takes a few hours in July to get over to cook. 19-21st is Harley rodeo and packed with bikers and would avoid if your coming around those dates. You would need to pay for a Yellowstone park pass and license. The park is packed that time of year 35-45mph if your lucky.
If rock creek is fishing well I would always recommend it here. The drive and views are hard to beat in Red Lodge. If you like to day hike there are some nice cutts in the area lakes though.