We live this way and do the trip regularly to Hungry Horse where we camp instead of West Glacier which is just a few miles away. The only tweak in your route I would suggest is instead of 29 slide over slightly to the east and taking 464 (Duck Lake Road) north instead of 29 and then cross the border through Carway. Then hit Fort Mcleod and north to Cowtown. It looks a little longer on the map but is actually quicker as it is pretty straight and only hilly. If you take 29 it is slow and winding and mountain driving and you have to deal with the inexperienced RV white knuckle drivers crawling along as it runs along the edge of the mountains. Lots of bicycles in the summer too to avoid and make it slow so if you want to make some time may not be the best route. Nice scenery though if you can do it in the early spring or September when no one is around. Duck lake Road you can run full tilt all the way north and still see the mountains on your left as you drive,
