John, the route you've chosen is good and 2 is scenic as well...especially skirting the park south on into West Glacier. Heading north on 89 takes you into St. Mary and access to the East Gate...that is 'Going to the Sun' road and close to large RV traffic...most all RVs. There are some great CGs on the East side but the ones we saw were sans full hook ups. Hopefully, you've got a couple of motors in that trailer...don't miss Going to the Sun.
We've been to GNP twice and like staying in Columbia Falls - more out of the park activities.
Edit: The road, off 89 into Many Glacier at Babb is scenic and where we saw our first grizzly on that first trip.
Jan and Bob