Djcjc, why 94? 90 will be much faster to get to Yellowstone. Any specific reason to go farther north?
As for the "easy 6 hours to Grizzly" - in my first post I mentioned going through Yellowstone being quite slow going. If you think you'll be much faster going around via Bozeman, you will be disappointed; going thru town there (which is what we needed to do going the opposite direction from 191 to I-90) is also slow going, lots of stoplights, traffic, etc. Maybe there's a bypass around Bozeman I'm not aware of, but even then - if you're starting that day anywhere east of Billings, it won't be any 6 hours to Grizzly. Just sayin'.