If you haven't bought or could change your air flights, check about flying into Fresno (FAT) instead of SFO. You'll save 3 - 4 hours (depending on city traffic) in getting to Oakhurst (I used to do that trip twice a week). Rental cars are probably cheaper, too. There aren't a lot of flights into FAT, but sometimes you get surprised and the airfare is close or even lower.
Do you have your Half Dome permits in hand? If not, you've missed the lottery by many months. (RANT WARNING) Due to a couple of morons offing themselves in afternoon thunderstorms, the Park Service is experimenting in how they can wring all the joy and fun out of a kick-in-the-pants dayhike to the top of Half Dome and they are succeeding. You have to get on-line months in advance, get in a lottery, pay fees, and the whole experience is more like buying tickets to a Springsten concert than a hike in woods. NPS says >400 people a day increases the risk and while that's true, it misses the bigger point: No one who leaves Happy Isles at 6 am (5 am is better), ever gets caught in an afternoon thunderstorm. Partly, they summit earlier. Also, someone being smart in one way, is smart in other ways. It is people who leave the trailhead at 10am who hike in the heat of the day, carry a honking big knife, go slowly, and (often) hadn't conditioned for the hike who can get caught on congested cables at 3 pm when thunderstorms can happen. END OF RANT.
We'll be going on August 16th. My 12-year-old has done the Grand Canyon in a day and won't have a problem. My 7-year-old has great strength to weight, but will want to climb every rock along the way. Mom might have to turn around with her. We'll leave Happy Isles at 6 or 6:30am. With adults only, I'd leave at 5 am. I've enjoyed departing at 2:30 am with a headlamp and seeing sunrise on top. I don't schlep water out of LYV, I use the spring on the way up. Post if you haven't read the guidebooks about that and PM me if I don't follow-up on said post.
Editted to add: I lived in Oakhurst in 1982, have been up Half Dome maybe 20 times, including 3 times in the last 3 years. Both sides of my family have been going to Yosemite for 4 generations. I understand that it can be "loved to death", but NPS's responses are so uncreative and unhelpful even if you accept their premise that idiots shouldn't be allowed to improve the gene pool by their actions.