The starting point for most ascents of Mt. Whitney (14,496 feet) is from the east starting at Whitney Portal (8000 feet). Whitney Portal is a campground, a store and a hiker's parking lot which is about 12 miles from the town of Lone Pine (4000 feet elevation) in Owens Valley on the eastern side of the Sierras. Whitney Portal is about a 7-1/2 hour drive from the Bay Area (going over Tioga Pass in Yosemite).
The round trip to the summit of Whitney along the main Whitney trail is 22 miles. There are a number of ways to do this 22 miles. Some people attempt it in a single day. They leave the trail-head at around 2-3am and hike the first couple hours by headlamp before sunrise. They plan to hit the Trail Camp camping area at 12,000 feet around 7am, then maybe get to the summit by 11-12am and get down before sunset or sometimes finish after dark by headlamp. The single day trip has a number of advantages. It's logistically a lot simpler because you only need a permit for one day, because you go lightweight for the entire trip and because you don't have to have any backpacking equipment. Lots of people try it this way. On our particular trip, I'd say that 2/3 of the folks were doing the single day.
Here's a look at the main trail from the Inyo National Forest web site:
Besides the obvious physical challenge of doing the whole thing in one day, the single biggest obstacle to any ascent of Whitney is altitude sickness. Above 10,000 feet and certainly above 12,000 feet, a significant number of people start having trouble adapting to the thinner air. Altitude sickness is something to be dealt with very seriously because, if the early symptoms are ignored and the ascent is continued, it can result in death. Basically, if you start feeling altitude sickness, you have to descend immediately. You can't wait for it to go away, you can't take some medicine for it - you have to descend (usually at least 2000 feet). There are two general forms of serious altitude sickness - cerebral (brain swelling) and pulmonary (fluid in lungs). With high altitude cerebral edema (HACE), you start to lose judgment and coordination. Many mountaineering accidents and even deaths on Whitney (two people died last year) are thought to be influenced by poor decision making because of the effects of HACE. With high altitude pulmonary edema (HAPE), you start getting fluid in your lungs and you simply can't get enough oxygen and you suffocate. HACE is more common than HAPE and the very early warning signs for HACE are a headache that just won't go away, even with something like Advil. Symptoms progress to the point where you can't walk a straight line and might even appear to be drunk. While science has not pinpointed any particular reason why some people get altitude sickness and some do not (it has nothing to do with fitness level), it has clearly shown that acclimatizing to your base altitude and then ascending slowly is the best thing you can do to improve your odds against altitude sickness. The ideal ascent rate is 1000-1500 feet per day. Since Whitney is a 6137 foot climb from the trail-head, you can see the challenge. Somewhere between 1/3-1/2 of those who attempt the summit don't succeed because of altitude issues. It is the major reason people don't make the summit.
So, since we weren't trying to cram the trip into a weekend and wanted to increase our odds against altitude sickness, it was an easy decision for us that we weren't going to do the single day trip. Then the question becomes how many days to you take to go up. A conservative plan would be acclimatize well beforehand and then hike up to 10,000 feet, spend the night at a camping area known as Outpost Camp, hike up to 12,000 feet, spend the night at a camping area know as Trail Camp, then go to the summit the third day. Slightly less conservative would be to hike up to Trail Camp at 12,000 feet the first day and then summit the second day. We decided that we would plan for a three night trip. If we got to 10,000 feet the first day and still felt pretty good, we'd see if we could go on to 12,000 feet. If we made it to 12,000 feet, we'd either summit the second day or we'd have a buffer day if the weather on the summit was lousy and we could wait it out.