First, I would skip Glacier NP and hit Cody. Figure 2 days for the Buffalo Bill Museum (tickets are good for 2 days). Across the street from it is/was the Bighorn Foundation Museum. A few miles east is Thermopolis which has 1) the Safari Bar, which was at the Holiday Inn==great food and many, many stuffed heads; (2) the hot springs (great fishing in the Bighorn River outside the resort and (3) a fantastic dinosaur fossil site. You can go south through the Wind River Canyon/Gorge..
Glacier is primarily a back-packers park. If Going-to-the-Sun Highway is closed (it often is), it's a full days drive from west entrance to east entrance.
Here's a few pics we took in Yellowstone:
A grizzly:
Another grizzly. This one came down the hill at an elk herd and started criss-crossing the meadow looking for hidden elk calves. First time I've heard a cow elk bugle!
If you want to be branded as a tourist, stop to take pictures of the buffalo. Oh, don't leave your car alarm on--the buffalo like to rub up against the cars.
The best spot to see Old Faithful is from the outdoor viewing area off the second floor of the Inn (which is the LARGEST log building in the world). When you enter the lobby, search the rafters. When the Inn was refurbished, a workman felt that every child should see a bear when they visited Yellowstone, so there is a teddy bear suspended from the rafters.
You MUST make reservations for dinner at the Inn. Otherwise, you'll be eating at 10 PM or so! Make them as soon as you get there! Tradition had it that for the first few years, formal wear (yes, tuxedos) was required for inside seating! The food is well worth it, also. The General Store nearby has a good burger and I hear the breakfasts are great!
The Firehole is well worth the side-drive. It and the Madison are great places to fly-fish. Licenses are available throughout the Park areas. If you fly fish, you MUST go into West Yellowstone and visit Bud Lilly's Fly Shop. Beware of the buffalo --they are
STUPID and
MEAN!.
Lamarr Valley is the best place to see wolves, especially at dawn.
The Beartooth Pass area is the route Chiedf Joseph took when he kicked the, er, "stuffing" outta the Cavalry!