Hi Anne,
Just got back from the park yesterday. Saw two huge forest fires, couple of bears, a moose and numerous mountain goats. My vertically challenged wife Liz and I made Siyeh Pass our first hike. We were warned at the info center about the narrow section but urged to at least hike up there and take a look. We came in through the Siyeh Bend side. Liz was not happy near the top when the trail got skinnier and the slope got more vertical. But we made it over the hump and I walked alongside of her on the ledge and kept her bumped up against the wall. Well-worth it because the descent was beautiful. I think there were three huge waterfalls in the distance. However, my toes were screaming for mercy after five miles of putting on the brakes downhill. Pretty windy throughout the hike, too. Much to my wife's chagrin, I held my harmonica out and let the wind play it for a few minutes on the trail. Had to keep removing my hat because of the gusts during the hike. As a result, I looked like a lobster from the neck up by the time we reached St. Mary's Lake and the hikers shuttle. Not a lot of shade once you clear the forest and it was hot all week there but a very pretty hike. Lyman's assessment of the ledge is very accurate.
Kudos to you for attempting that hose section of the Highline Trail!
Mick