Recreation: Rush Hour in the Wilderness

"All sorts of human stuff is being poured into our valley this year," lamented Conservationist John Muir about the crush of crowds in California's Yosemite Valley. That was in 1870, when Yosemite counted its annual visitors in the thousands. This year 1,700,000 people are expected to come geysering into the national park, and the overcrowding is becoming so severe that many will wonder why they ever left home.

The trouble is that though Yosemite sprawls over 1,189 square miles, more than 80% of the visitors insist on huddling together in one seven-square-mile...