FYI - Alpine Grades refer to the amount of time spent doing the technical part of the climb. Trail hiking and approach time does not count. A Grade III climb involves nearly a full day on technical ground. See this link for definitions and examples:
Handy Alpine Grade Facts
FYI, Back country camping in Glacier is not free. There is a fee of $5 per night per camper.
There is an additional fee of $30 for advance reservations for a backcountry trip.
You state that no grizzlies will be found on Lone Walker mtn, but since they appear to visit nearly every other mountain in the park, that may not be a correct assumption.