Glacier National Park

Pros: Gorgeous lakes, rivers, mountains, incredibly scenic drive, neat wildlife, great camping.
Cons: Short season, not many services in or near the park, not good for horseback riding.

Whether you just want to drive the Going to the Sun loop over the Continental Divide or spend days hiking or camping in the park, Glacier is worth a visit. Lake McDonald is a great place to throw your kayak in the water, the park has miles of trails for all kinds of hikers, and the weather is fantastic in the summer. Glacier lacks the geothermal activity of Yellowstone but makes up for it with its sweeping views and beautiful glacier-capped mountains. If you're not camping, make reservations early because hotels are few and far between and fill up fast during the summer months.