If you end up going from Jellystone to Glacier I recommend coming in from the West Yellowstone entrance to Butte. This will bring you through Montana's Virginia City following Hwy 287. From Butte go to Anaconda to see the big smelter smoke stack and see the pile of black tailings, this is State Route 1. Then continue on that road to do the Pintler Scenic Loop. You will come back to I-90 close to where you need to head north to Glacier. Take Hwy 83 on the east side of Flathead Lake it's more scenic and less full of summer cabins than going up Hwy 93. The Road to the Sun in Glacier is beautiful.