Beautiful view of Missoula especially at night even just from the M. To the summit, there are two main paths from the M that get you up there one is easier but the path is longer and it does come across a cool yet short cave. This Map of the trail is a little out dated when it comes to hiking to the summit since there has been trail restoration and land preservation efforts, but if you are not sure just ask somebody around you they are all pretty nice!
A beautiful and challenging trail, especially during the winter months. I remember exerting much more effort than was necessary in order to avoid the patches of ice and snow mixed with mud.
The view is worth it from the 'M' alone. Pushing yourself to the top of Mt. Sentinel results in astonishingly gorgeous views. Well worth the added effort.