Last time out to the GNP/Whitefish, MT area, we stayed at a ski resort (in the summer), that boasted mountain biking and hiking... and a couple of other less-known activities. One of which was called A Walk in the Treetops - platforms in the treetops on which you can walk, and the views are said to be phenomenal. Sadly, the day we did this was very foggy and overcast, and we saw nothing. It was eerie and creepy, but yet still kind of neat to do. The thought this time is to make a second attempt at this, but only if the weather cooperates with us. I already know what fog looks like from 150 feet off the ground.
The resort also has a couple of Zipline Tours which might be fun... and also something called an Alpine Slide. Both of which would be something to look into if we decide to spend part of the day on the mountain.
We're looking at taking some the forest service roads in and around Hungry Horse Reservoir, which is near the southwest part of Glacier National Park.
Down near the MT/WY border are a couple of other places that I've been advised to check out... a couple of those look doable. We can pair Beartooth Highway near Cooke City, MT with the rough road up to Hellroaring Plateau. The road to the plateau is said to be jeep-trail worthy... so of course it's an automatic must-do in my book.
Aside from all of that, I'm still getting feedback daily about forest and other roads in various areas that we should look into. All this makes me wish we had more than just the week or so to play... but then again, we'll have something new for which to return. That works for me.