The Apgar Visitor Center (406/888-7800) has park rangers on duty 8 a.m.–7 p.m. (shorter hours during the spring and fall, weekends during the winter) to answer questions and suggest hikes; pick up backcountry permits at the nearby permit office (406/888-5819).
Park shuttles depart from the Apgar Transit Center (6:45 a.m.–11:45 p.m., free), which serves as the transfer point between two of the three shuttle routes. The Apgar Route provides local access to Apgar Village [1], Fish Creek Campground, Apgar Campground, and the transit center.
The Lake McDonald Route travels between the Apgar Transit Center and Logan Pass [2], making several stops along the way. At Logan Pass riders can transfer to the St. Mary Valley Route to continue along the Going-to-the-Sun Road [3].
Although these are not interpretive tours [4], shuttle rides provide a great way to get to and from hiking trails.
Links:
[1] http://www.moon.com/destinations/montana/glacier-national-park/lake-mcdonald-valley/sights/apgar
[2] http://www.moon.com/destinations/montana/glacier-national-park/logan-pass-st-mary/sights/logan-pass
[3] http://www.moon.com/destinations/montana/glacier-national-park/lake-mcdonald-valley/sights/going-the-sun-road
[4] http://www.moon.com/destinations/montana/glacier-national-park/exploring-glacier-national-park/getting-around/commercial-van-tours