Different people find different things to be the best guided tours in Yosemite, but there's a lot from which to choose. There's nothing like getting out on foot on a ranger walk for an hour or two and this experience should be at least sampled in any national park visit; some might make attending ranger walks a full summer-long educational experience. There are great ranger programs in Yosemite Valley year 'round, and in the summer at Wawona, Tuolumne Meadows, Crane Flat and White Wolf. In the winter rangers do 2-hour snowshoe tours at Badger Pass Ski Area.
The park's concessioner, DNC also has a 12-month bus tour operation. In summer, the Grand Tour gets you from Yosemite Valley to Mariposa Grove and to Glacier Point. Their most popular offering is the Valley Tram Tour (fondly called "Green Dragons") which runs several times a day and goes for two hours to see the main sites in Yosemite Valley. The open top flatbeds provide a unique view of the Valley's cliffs and waterfalls as you cruise around at a mellow speed. Rangers do the narration, so it's quite good.
DNC also has horseback trips where the local wranglers will show you the sites along the trails in Yosemite Valley, Wawona or Tuolumne Meadows.
Increasing numbers of people (and travel companies) are hiring a private naturalist/guide from the park's non-profit partner, the Yosemite Conservancy to show them the park in-depth. They employ a cadre of local specialists: photographers, naturalists, authors, off-duty rangers, etc. who know the park well and are great communicators.
PO Box 230
Fun field courses that'll help you get deep into Yosemite... read more
Bus tours with veteran drivers and knowledgeable guides... read more
Mariposa Grove Road
Park at the Wawona Store parking area and walk east 0.25 miles to Forest Dr. The trail head is on the right