Denny Shaffer, president of the Sierra Club, a 340,000-member national organization that lobbies for environmental concerns, spends about one-third of his time at the club's headquarters in San Francisco. Fortunately, that's his favorite city "because of its beauty and its freshness . . . it's so easy on a day off to visit Muir Woods, Point Reyes, or Point Lobos near Carmel."

But Shaffer, whose home is in Fayetteville, N.C., chooses to vacation away from cities when he can. "I'm a walker. I enjoy getting out in the wilderness. I am, by nature, the kind of guy who, when he gets up in the morning, hopes to do something that he has never done before. I feel that way about the time I have to spend on recreation."

Shaffer says when he is in an area, "I talk to the people there and ask them, 'If you were going to take your kids to only one place, where would it be? What's your special place, your special mountain, your special river?' Frequently they say 'there is a place I love but I'm worried to death about it,' " referring to possible environmental damage from logging, mining or mineral leasing.

Some of his own "special places:"

* Carolina barrier islands: "Every winter, in January, I'm on the Outer Banks or one of the barrier islands of the Carolinas. The migratory birds are in, and you can walk for miles without running into another human being. For a few brief moments you have an idea of what the coast of this country was like at one time."

* Yosemite National Park: "I spent a week backpacking in the high country of Yosemite in the fall. I climbed up one of those high rock cliffs and was overwhelmed by the grandeur."

* Alaska: "If I dream about what I'm going to do . . . well, I haven't seen Alaska. I'm going to get there very soon. It's something I've just got to see."