OP is from Australia per her other post.

I allow about an hour to get out of LA from LAX. It could be less but you never know.

From Sylmar to Fresno there won't be much traffic, takes about 3 hours.

From Fresno to Oakhurst is another hour. So that might not be a bad first night stop.

Or they could go a bit farther and stay in Wawona. However
I probably wouldn't want to drive into the Valley after dark, but in summer it might be okay. Add another hour since you aren't likely to go over 25 mph for that stretch.

Unless they changed their plans, the family is spending the first night in L.A. before driving to Yosemite.

I agree with jamie99 that if you could push the trip back a few weeks many things would be easier, less crowded and possibly cheaper. The weather will still be very good and temps generally still warm-to-hot.

Thank you so much everyone for your replies!

to answer a few questions:
Yes I am from Australia.
Unfortunately due to leave from work etc, we are locked into Mid-Aug to Early Sept 2016, give or a take a few days either side.

Thanks for the SF accomodation suggestions, I will look into those.

We did look into flying in and out of SF instead of LA but it a lot more expensive for us.

I will definitely be reviewing the driving times, its very handy to know about the summer holidays and the national holiday during that time.

So much to think about!
Thanks again!

If you want to do a loop starting and ending at LAX, begin your trip driving up Highway 1 to San Francisco.

Then drive to Yosemite from San Francisco (as somebody else noted, it is better to go to Yosemite from SF than from LA).

From Yosemite, drive over Tioga Pass to Death Valley, Las Vegas, and the rest of your trip.

I believe you will have a better experience if you take the time you have set aside for San Diego and spend it enjoying the natural wonders of Utah and Arizona.

Two extremely worthwhile attractions you have not included in your itinerary are Canyon de Chelly (which I mentioned earlier) and the Valley of Fire, which is near Las Vegas.

HTtY

If you want to stay at a motel with complimentary parking in San Francisco (such as the Columbus Motor Inn), book well in advance of your arrival. The same goes for Yosemite and most of the other places on your itinerary.

HTtY

I think with little kids San Diego would be a good choice (and better weather in summer).

Are you arriving on a Friday or a Saturday? (your dates are off in the OP, 22Aug is not a Sunday). Friday afternoon is not a good time to "explore L.A" by car. Especially if you've just flown from Australia. If you don't want to hit the road immediately and head north, look into the Sheraton or the Four Points near LAX, they have a "24 hour" offer where you are allowed to check in in the morning and check out 24 hours later. The kids could nap and then in the afternoon you could explore Santa Monica or Manhattan Beach.

In case you were thinking that Hearst Castle might be fun, it won't be with kids. There are many, many stairs and no real way to use a stroller there. I have seen parents trying to carry kids and strollers up the stairs and everyone looks miserable. There is a movie you can watch about the building of Hearst Castle that might that is shown every fifteen minutes or so in the visitor center that may suffice for you to learn about the castle, if you're really interested.

My best advice on any trip with kids that age -- always make sure your lodging has a pool. Makes for happy kids who sleep good!

In fact strollers are not allowed on any of the tours.

I don't entirely agree with janisj about Sacramento- I got a kick out of Old Town and the train museum would have been a big hit with the kids in my family. I adored the Crocker- thanks, janisj -but I wouldn't want to take a toddler there. And that's not because it's an art museum- I'd take kids to many art museums that I've visited- it's the feel of the place. Not sure how to explain it.

If you do go to Fresno, I found the Forestiere Underground Gardens a whole lot more interesting than Hearst Castle.

I think Columbia Historic Park would be fun with kids as well if you have the time.

And the one place I'd definitely take kids to in LA would be la brea tar pits and the Page Museum. LA county art museum, right next door, is one of the art museums I wouldn't hesitate to take kids to. Found it uniquely Californian and very mutimedia oriented. (Um, in other words, it's weird, wacky and wonderful all at the same time lol).

Forgot to say that I kind of agree with people's comments on driving times. Specifically, I think you need at least one more day in Yosemite for the sake of sanity. For one, the crowds are seriously crazy. Think Disney crazy (at least in the Valley). And second, google maps totally lied to me about the time it takes to get from Sacramento to Yosemite- due to procrastination and crazy traffic, I ended up driving into Yosemite in the dark and that was one of the more terrifying parts of my trip. I'm a little concerned you have so little breathing room in your itinerary- I've always needed fewer one nighters and more "just in case" time when traveling with little kids!

Big sur- depending on where you want to stop, you may NEED a night there (do not attempt in the dark). However, I think Monterey/Carmel is much better for kids. I would not have enjoyed Big Sur at all as a kid- it's all about the views. And I wouldn't want to drive it with an unhappy toddler in the backseat. Carmel's got a beach; Monterey has the excellent, hands on aquarium as well as multiple candy stores


I also don't know if it'll make much sense outside of my head- but I think I'd skip Santa Monica, do Disneyland, then do San Diego and do LA. For one thing, I think Disneyland would be a really nice (and welcome) break from your car at that point. Heck, maybe skip sightseeing in LA all together and put in some serious beach time somewhere (maybe Coronado?) 1 and 3 yr olds can play happily in the sand for hours- but may be more inclined to melt down at crowded attractions. That could be me though- I'd rather help them build sandcastle than go to multiple amusement parks at that age.

For Monterey - There's this really good breakfast place called the Breakfast Club. Big selection of food and bottomless coffee refills. http://www.breakfastclubrestaurant.com

For SF - If you could go without a car, that would be best. Parking is tricky, but in downtown, there are a lot of parking garages.