We were at Glacier a few years ago with my sister and her husband. He can't hike, but still enjoyed all that he could see from our Jeeps. We did a day trip from the KOA on the est side up to Waterton. Beautiful place and so worth going. One of these days when go back, we'll spend a couple of nights up there to have a chance to do more than we had time for.
We've been Yellowstone 3 times, in 3 different seasons, and I can easily say it's our favorite place to go. We didn't see nearly as much wildlife in Glacier and we did in Yellowstone and the Tetons. So don't be disappointed if you don't either. The scenery makes up for it.