The only way to access this 30-mile stretch of wild glacier-green waters is by bush plane or horse. It's worth the effort. Early-season trips mean riding booming Class IIIs and Vs through limestone gorges; late spring and summer bring spectacular fly-fishing—cutthroat trout grow as long as 22 inches. Chances of seeing other people? Low. Chances of seeing a grizzly? High. The Glacier Raft Company will fly or horsepack small groups in for multi-day rafting or guided fishing trips (glacierraftco.com).