I'd say yes, 17mm, if used properly, will be great! Here's a couple 17mm shots from glacier. . .
Keep in mind that you need to check with the NPS GNP on road closures, the Going to sun road is not even open yet due to fall storm damage. GNP says around the first of July, some of the crew says mid July before the road is open all the way over. It likely will open on the west side by july 1, but the east side may not yet be open. . . Also, there is limited off trail access on logan in july as well as not very many flowers yet to shoot. . .
I'd be heading for many glacier if I were you. . .
And another. . . You may recognize the falls shot, one like it shot by Gallen Rowell was on the cover of OP a las year.
You wont be able to get either of these shots. First off, the areas where they were taken are closed, and second, they both were taken in LATE August, like the last few days of August. . .
In any event, back to your post, the 17 will do wonders!!!