While i know the big suggestion is the Highline we really enjoyed going up to Piegan Pass instead. Multiple Glaciers, very few people, and you get to walk a couple miles on the CDT... Some start at Siyeh bend, go over Siyeh pass and down to Sunrift Gorge, seemed like most of the few hikers we saw were headed that way. This is a little shorter and less elevation.. WHY i chose this route/ Mainly i wanted to be in some deep Montana Forest, and i wanted a good look at a Glacier or two./ it's not all about the views- and then there are the Views/ Wow, Piegan Pass is spectacular. Photos and videos made me want to see it in person and yeah/ better in person. The elevation is just enough you feel it and looking over that drop/ Wow. See Piegan Glacier along the way with views back to Jackson. The side leg down to Jackson Glacier Overlook looked like it saw even fewer people, was way overgrown- did not impede travel but made you feel that much farther away from it all even when only a mile from the road.
Approximately 9 miles round trip with around 1700 feet of elevation gain/loss. Afterwards we ended up taking the shuttle east from Jackson to St Mary's and back just to see the sights/ Fantastic. Saw a grizzly from the bus. While we skipped the Highline, Hidden Lake Overlook is of course recommended and a hearty hiker could knock both of these out in one day. I suggest making that a LONG summer day though// was really nice to take it slow and enjoy being there. Deep forest, some big exposed views, talked to some CDT thru hikers and one guy who day hiked to Piegan Pass from Many Glacier- a Very Long DAy hike!! / and Glaciers... Highly recommend it if you are looking for something a little out of the way and don't mind being in deep forest without a view for much of the hike.
I have a video of the hike but it is pretty long so there are links in the description which will skip you ahead to the highlights.
There is more stuff from Glacier in the playlist some you might find useful but most are of the standard tourist sites.
video here https://www.youtube.com/watch?v=vpuJvE6 ... vR&index=3
Had planned to post this at the start of this season but better late than never i guess, Piegan Pass will be there for an epoch or two i think.