We hiked Mt. Dana on August 1 this year. The trailhead is at elevation 9,945 feet and the summit is at 13,053 feet, meaning you gain 3,100 feet in about 3.25 miles (6.5 mile round trip). As you can tell from that basic information, the trail is very steep throughout most of its length. We climbed it two days after Mt. Whitney, and I can assure you that it will make good training for Whitney. In fact, while the Mt. Whitney Trail is much longer and the total elevation gain is more than twice as much as it is on the Dana trial, there is almost nothing on the Whitney trail that seemed as steep to us as the Mount Dana trail seemed along most of its length. Parking for the trail is available immediately south of the Tioga Pass entrance station to Yosemite National Park. The trail begins on the other side of the street, just east of the entrance station. The trail is not "official," meaning you won't find it on most maps, but once you find the beginning of it east of the entrance station, it is easy to follow. After a short, fairly level section, you will reach the "garden" area, which is filled with beautiful wildflowers, but will be the beginning of the steep section. After two miles, you will reach a plateau witha huge cairn. The trail becomes very difficult to follow at that point, but since you are above treeline, the top of the peak is easily visible, and it's mostly talus and boulders on the way up, you can pretty much pick your own route withour any fear of getting lost. We suggest using trekking poles. We got rained on, and the poles were very helpful on the way down when the trails were slick, since they are so darn steep! Good luck!