Move Glacier to the top of your list and, if you possibly can, go during the last week of September. That is your best bet at peak fall foliage, it will feel like you have the park all to yourself, and you are almost guaranteed to be serenaded by bull elk, since it is the rut.
Have you ever been to the San Juan Range near Telluride, Ridgway, Ouray and Durango? The San Juan Skyway, a 236-mile loop, is one of the great alpine drives in all of America, and it is particularly magnificent in fall, which, in that corner of Colorado, tends to peak around the first week of October. The Sneffels Range is the most impressive and rugged portion of that mountain range. If you have not already done so, be sure to take the Durango & Silverton Narrow Gauge Railroad. We rode it last fall and had the pleasure of riding in one of the two surviving, original cars. Although refurbished in terms of seating, the car itself dated to 1883.
The Sawtooth Mountains in central Idaho are magnificent as well. They are very reminiscent of the Tetons, due to their having been formed in the same way (i.e. fault-block formation). The Sawtooths are about three thousand feet lower in elevation, but they are just as rugged as the Tetons and, like them, rise without foothills.
I have been to Crater Lake and the brilliant blue of that lake truly defies description. The only times I have ever witnessed alpenglow was during a fall 1976 visit to Mount Rainier. Talk about your bucket lists for backpackers; the 93-mile long Wonderland Trail (
https://www.wonderlandguides.com/hikes/wonderland-trail) circumnavigates Mount Rainier.
