3 Nights in Glacier recommendations…

The route you have is good one, but in my opinion I think you would be missing some of the best things that Glacier has to offer (mountain lakes, rivers/streams, etc.) with those locations. One other thought I have is that if youare cpable of 15 mile days the proposed route will result in some very short days of no more the 2.5-4 hours of hiking assming a 2-3 MPH pace. Having said that I tend to be more distance and speed oriented (20-30 miles per day) when I hike so take my suggestions with that in mind

An additional thing to take into consideration with Glacier is that it can be difficult to gain site permits during the busy season. Make sure you have multiple itinerary options on your application to maximize your chances of getting a reservation. If all else fails still go on your planned dates and just make sure you are at the backcounty office an hour before it opens as they keep a certain amount of campsite available for walk-ins on a first-come-first-served basis. This is actually what I have had to do for every trip I have taken to Glacier as I have never been lucky enough to get a reservation.

With all of the above being said here are some additional route options that I think are exceptional in what they bring to the table.

Option 1: This one is a classic route that can be difficult to snag permits for. It can also be done in reverse if you should so choose.

Day 1 Many Glacier Lodge to Fifty Mountain. 19.5 This would be a very long day but once you get over Swiftcurrent Pass it is actually  a pretty easy hike from Granite Lodge to Fifty.

Day 2 Fifty Mountain to Glenns Lake HD 14.4 Miles

Day 3 Glends Lake HD Lake Elizabeth (ELF) 7.2 Miles

Day 4 Lake Elizabeth to Many Glacier via Ptrarmigan Tunnel 8.5 Miles

Option 2: A slight variation on option 1 with you spending a night at Stoney Indian Pass (which in my mind is one of the coolest campsites in the park and has one of the 5 best pit toilets I’ve ever used). This one could also be reversed or days 1 and 2 altered slightly to change your mileage.

Day 1 Many Glacier to Granite Park Chalet 7.6 Miles

Day 2 Granite Park to Stoney Indian Pass 20.1 This would be a hard day with the final climb up to Stoney Indian being quite difficult but with an early start it would be very doable.

Day 3 Stoney Indian to Lake Elizabeth 10.3 Miles

Day 4 Lake Elizabeth to Many Glacier via Ptarmigan Tunnel 8.5

Option 3: This one would have you setting up a base camp at Glens Lake FT and day hiking out from there which give you the benefit of essentially no pack weight on days 2 and 3.

Day 1 Many Glacier to Glens Lake FT via Ptarmigan Tunnel 15.7 to set up base camp.

Day 2 Hike up to Stoney Indian Pass and back to camp 17.6 Miles

Day 3 Hike to a little lake south of Mokowanis Lake (I am currently forgetting the name) and then back to camp. Between 10-12 Miles

Day 4 Glens Lake Lower to Many Glacier 15.7

Option 4: This one requires hiring a taxi to take you up to Kintla Lake while leaving your car at Lake McDonald. However, it does allow you to access some of the more unsed areas of the park which has some great appeal.

Day 1 Taxi Ride to Kintla Lake trailhead and then hike to Bould Pass  17.2 Miles

Day 2 Boulder Pass to Waterton River or Goat Haunt 13.7-14.2 Miles depending on campsite

Day 3 WAT or GOA to Fifty Mountain 11.1 Miles

Day 4 Fifty Mountain to road via Flat Top Mountain 12 Miles. Then take the shuttle back to your car at Lake McDonald

I know the mileages on these are a bit more than the route you proposed, but I have done some variation of all these options and can say from personal experience that they are completely worth the effort. Keep your pack weight to under 30 lbs at the high end and between 16-20 lbs if at all possible and it is definitely achievable.

Best of luck.