I'm pretty sure all the lodges are booked, perhaps not, but if I were heading to Montana there's only one place I would go....Glacier National Park.
East? Glacier Lodge
Here's a small portion of the main lobby in East Glacier Lodge. Notice the size of the trees.
Many Glacier Lodge
Prince of Wales Lodge (on Canadian side of park)
This is "Going To The Sun Road" which takes you over Logan Pass. It is truly an amazing stretch of highway.
As a kid we would tent camp for 3 or 4 days...then stay in one of the lodges for 1 night. Oh...and watch out for the Grizzly Bear when camping. My sister used to work at this park and she lost a close friend to a Griz here. It is a very very rare thing to happen in North America, but it can.
My sister and I were on a day hike out of Many Glacier Lodge one time when we came around a bend in the trail and there not 25 feet away stood the largest Griz my sister had ever seen (she used to be a Ranger). Scared the crap out of us, but the Griz took one look at us and ran straight up the side of the mountain moving faster than we could ever run (although you should never run).