I've been there twice, spent 10 days there hiking in 1994 and then in 2019 we were across the border at Waterton, AB and went down to Glacier for a day.   I couldn't believe how much it's changed in those years.   Way too many people now. 

We always go for the hiking and don't do much scenic driving.  The problem with Glacier is the infrastructure hasn't kept up with the crowds and  funding is sorely lacking.    It's still a beautiful park but Going to the Sun Road is impossible and even finding parking at the trail heads is a problem.

As to where to stay, we always tent, but in '94 we had people with that stayed in a hotel just outside of St. Marys.   Better get reservations early.  And enjoy before Glacier is completely trampled.

Edit to add the rafting trips on the west side of Glacier are great and I highly recommend