Ponzy, you've gotten a lot of excellent advice from the responses to your post, so not much to add except: be cautious about overdoing it just prior to Whitney. You'll be surrounded by a vast array of cool, tempting hikes, but remember why you're there. Keep any warm-up or acclimation hikes to a minimum in the 48 hours prior to your goal. Dayhiking Whitney is strenuous and your best chance of success is to keep your legs fresh.
Maybe something mild (Lone Pine Lake OAB) two days before Whitney, and virtually nothing the day before, especially since you'll have a very early wake-up ahead of you.
I mention this as a fellow eastern lowlander who heads to Cali each year for some Sierra fun, and we just cannot train and prepare to climb a fourteener like our brethren to the west. I feel your pain, brother. Every year, my first couple of days at elevation has me dragging pitifully. By day 4 I'm reasonably well acclimated, and sleeping at 12K' and hiking to 14K' isn't a big deal. Cut two days acclimation off that schedule and it's torture trying to go above 12K'. Harvey hit it dead-on (as you would expect from one of the leading experts in high-altitude medicine) - acclimation first, especially for a lowlander. Hydration, pace, fuel are all important, but if your body's not ready for the elevation you're likely toast. Given the fact that this will be your first attempt at these elevations, I can't over-emphasize the acclimation factor.
Best of luck. I'll be out there the last two weeks of July, so hopefully I can hear your success story at the Portal over a beer.
Gary
