bigsky Loc: NW Montana

All previous suggestions are good ones. I will be there a couple of times in August also and would add the following to what has been posted
Entering the west entrance stop at the information center a mile of so down the road to get any questions answered. From there detour to Apgar (1/2 mile)which is at the foot of Lake MacDonald for a good photo op of lake and mountains. Heading along the Going to the Sun Road 10 or so miles past the end of lake Mac Donald stop at Avalanche campground and take the trail of the cedars about 1/3 of a mile to Avalanche creek gorge for another photo op..If time permits take the trail to avalanche lake for about 200 yards to the area above the gorge.
Further along the sun road you will come to the visitors center at logan pass. From here you can take the trail to Hidden Lake overlook mentioned in one of the previous posts.Another scenic trail from the center is the Highline trail to Haystack and back but is an all day event.
From the visitors center you will head toward St Marys driving along St Marys lake. About 2/3rds along the lake stop at the Wild Goose Island scenic overlook. This is a small island in the lake and the scene is reportedly the most photographed scene in the park.
From St Marys you should head for Many Gacier,/Swiftcurrent about 15 miles. This is one of my favorite places in the park unless I am in the backcountry at the chalets. From here are the trailheads to Iceberg Lake,Grinnell Glacier , Cracker Lake and Swiftcurrent Pass. If you are in the Swiftcurrent campground area it is wothwhile to walk the 1/3rd mile to Fisher Cap lake for a chance to photograph a moose.
Enjoy!