People visit these parks to witness their beauty, and that can be done in a host of different ways -- you don't have to hike 5 miles or climb to the top of a waterfall. Some of the most rewarding moments come from quiet, still observation.
Be sure to inquire about the National Park Service's free Interagency Access Pass, available to the blind and permanently disabled.
In Yosemite, there are some fairly level paved trails around the valley floor, including the ones to Mirror Lake and Happy Isles, and the paved bike trail is also accessible to wheelchairs. Ask for information on accessible points when making reservations. An accessibility brochure is available at park entrances and visitor centers, and wheelchairs can be rented at the Yosemite Medical Clinic (tel. 209/372-4637) and the Yosemite Lodge Bike Rental Stand (tel. 209/372-1208).
Wheelchair Getaways (tel. 800/642-2042 or 859/873-4973; www.wheelchair-getaways.com) rents specialized vans with wheelchair lifts and other features for the disabled, with outlets in most Western states.