I agree. Morningstar is a very nice place, and we saw both moose and mountain goats a few years back.
Atlantic makes the hike to/from Red Eagle much more doable, plus the walk up to Medicine Grizzly is nice, and the fishing is very good.
The hike from Red Eagle foot to Reynolds is long, but not overly strenuous. After the hike back from Red Eagle to the trail junction, there is some up as you go over a fair sized hill, and then down to St Mary's Lake. The St Mary hike is very flat, and the one time I did it, we didn't see anybody until we hit the Falls. Red Eagle to Gunsight is way too much, unless you are in great shape and get an EARLY start - it's about 19 miles.
The key is to realize you're only about 1 mile away from the Sun Road when you are at Reynolds. Stage a car at Jackson overlook with supplies/clothes. Have a couple of your faster hikers go to the car and resupply the morning after your stay at Reynolds. Then, you're only packing for two 3 day hikes, instead of one 6 day hike (or whatever). This step made both hikes easier and faster.