LA/SFO 2 week itinerary
 

Grand Canyon is about an 8-9 hour drive from LA, even from Las Vegas it is a 5 hour drive to the South Rim, where most of the lodging is. You need advance reservations to stay overnight at the Canyon, make them months in advance.
Same for Yosemite, it is about a 4 hour drive from San Francisco and lodging books up a year in advance, so make your reservations now, you can always cancel if your plans change (do not prepay the rooms).
Your 5 and probably 7 year old will need booster seats in cars, taxis, Uber and Lyft do not provide them. You can buy inflatable seats like Bubblebum. Whether you can get by using public transport depends on what you want to see besides Disneyland.

On our trip to Arizona early last month, my wife and I flew to Phoenix and rented a car there to go to the south Rim of the Grand Canyon, Sedona and several other neat places in Arizona. We stayed in Flagstaff for 6 nights since we didn't have reservations at the Canyon.
If you wanted to take a train overnight, you could go on the Amtrak Southwest Chief from Los Angeles Union station to Flagstaff Arizona.
If you chose Yosemite over the Grand Canyon, you could take an Amtrak bus north from Union Station to Bakersfield to get on a San Joaquin train to Fresno where you can rent a car to go in through the south entrance. There are Park Service buses to get around inside Yosemite.
Once you leave Yosemite, you can return the car and take another San Joaquin train to get from Fresno to Emeryville with a bus connection over to San Francisco. (note that SFO is the airport designation and not the name of the city of San Francisco).

Hi, we are Australians too and have had a few driving holidays in America. Generally speaking, you are much better off hiring a car. America (apart from the big cities like New York) is geared towards cars and freeways, rather than public transport. Public transport exists but with a car you can be much more flexible. With two adults, one person can be driving and watching traffic while the other is navigating and saying "keep right, keep right" LOL. You do have to be careful but if there are other cars in front of you, you just follow them. If you are pulling on to an empty road, that's when your instincts can get you in trouble (we did it once, pulled out on to the left. All was fine but we were extra careful afterwards).

Looking at your plan, you could get a shuttle bus from the airport to your hotel in Anaheim. Then use shuttles around the area, they are very common in the touristy areas and easier than driving, parking, getting lost etc. Then when you are leaving Anaheim, you could pick up a car then and drop it back before your few days in San Francisco.

I'd work out how many nights in each place, two nights gives you one full day, three nights is two full days etc. You might also want to recover a bit from jetlag when you arrive, if you are all tired and your body clock is out of whack.

There is a great free car museum in Sylmar, which is on the northern outskirts of LA. It's a long way from Anaheim but might fit in with your plans. Check out Nethercutt Museum reviews, we really enjoyed it. You could spend some time driving along the coast, Big Sur is beautiful with great views and the Hearst Castle near Cambria is amazing. Not sure how much your kids would enjoy it but you could check it out online. We've been twice and would go again. The aquarium at Monterey is popular. Yosemite is beautiful, lots of easy walks, waterfalls, squirrels, etc. You could drive up the coast road then cut across to Yosemite after Carmel/Monterey. Then back to SF for a few days and fly home.

Kay

Just quick . . . one day in Yosemite verges on 'why bother' territory. It will ether take nearly a full day to get there from LA or half a day to get there from San Francisco - so staying one night will give you at most a few hours in the most glorious part of your whole itinerary. The waterfalls will be ROARING and there could be snow. The back country will be closed but i would not even consider Yosemite unless you can stay two nights and squeeze in 1.5 days for Yosemite Valley.

I don't think you can fly direct from Australia to San Diego. So you'd have to fly into LAX then get a domestic flight. Not such a bad thing but it all takes time out of your trip. Be aware of luggage restrictions on the domestic sector, we nearly got caught out in Denver once, flying back to LAX. Luckily I had paperwork from Qantas to say we were on one ticket and what was allowed, the check in guy was not happy. He was insistent we pay a large sum of money for our bags.

Yosemite is closer to San Francisco but it really depends on how your trip pans out, what order you decide to do things. You can also drive from LA up the eastern side of Yosemite and enter that way. Most people enter the park from the western side. We stayed a few years ago at June Lake, on the eastern side and loved it. You'd need to allow extra time to travel this route. Just heading across from SF will be much quicker.

What sort of things do you want to do in LA? If you've already seen the major things on your list - Disneyland etc - then maybe reduce time on this part of the trip. If it was me, I'd take one night from SF and add it to Yosemite.

Kay

Just FYI you cannot enter Yosemite directly from the east in April as Tioga Pass is closed. April is winter in the higher elevation areas. Entering from the west you could still encounter snow. Check the forecast and road conditions to decide which route to take. Hwy 140 is the lowest elevation route into Yosemite Valley.

I think it is easier to get from San Francisco to Yosemite than it is from LA. Could you reverse the order going to SFO first? I see no need to stay in San Francisco for more than 3 days/2 nights.
It is possible to get from San Francisco with an Amtrak bus to Oakland to get on a San Joaquin train to Merced. There are YARTS buses that travel from Merced into the Yosemite Valley with several stops including El Portal where you might have to stay if you can't get lodging inside Yosemite.
Leaving Merced (or Fresno), you can get a San Joaquin train south to Bakersfield with a dedicated bus to take you to Los Angeles or Las Vegas if you wanted to also visit the south Rim of the Grand Canyon with a rental car.

Even entering Yosemite from the west could present a problem in April. Tire chains might be required, but car rental companies don't allow the use of tire chains on their cars. You'd have to independently purchase tire chains, and, if you did use the chains, whatever insurance coverage you purchased would not cover any damage to the vehicle that might occur.

Alternatively, follow tomfuller's info, stay in El Portal and take the YARTS bus to/from Yosemite Valley.

https://yarts.com/routes-schedules/

I would try to organize your time in Yosemite as late in April as possible.

https://www.nps.gov/yose/planyourvisit/april.htm

From Los Angeles you can enter via Oakhurst, where some people often spend a night to start.

Chances are you will not be able to drive to Glacier Point or the Tioga Pass in April.

However, by mid April there is a good chance that you could see Mariposa Grove if you come in from the south on the Wawona Road. Bridal Veil Fall has a short trail from a parking lot at the southern entry, and loop back around to the Yosemite Falls without having to deal with Yosemite Valley traffic jams . Since much of Yosemite will be closed off in a heavy snow year, you don't need to stress about only having 2 or 3 nights (or even one).

While Tom certainly has his areas of expertise, this is just a personal preference on his part and, I suspect, not the opinion of most of us here. I'd encourage you to stay in SF the 5 nights you've allotted.

The problem with hwy 41 is the altitude goes over 6,000 feet so if there is a spring storm there will be chain controls for sure. Hwy 140 hugs the river and is much lower in elevation.

I suggest putting off the decision until you're there. If you find you really want less time in SF drive north across the Golden Gate to Wine Country & the Sonoma County coast for some beautiful scenery & interesting smaller towns. More information about your interests would help with suggestions. But, really, you may find you don't want to leave the City.

Amtrak bus from Los Angeles Union Station to Bakersfield to connect to the San Joaquin train to Merced. The YARTS bus picks up at the Merced train station to take you to El Portal or on into Yosemite Valley.
When leaving Yosemite take the YARTS bus back to Merced and the northbound San Joaquin to Emeryville to connect with the bus over into San Francisco.
Hotel rooms in San Fransisco are known to be expensive. There is one San Joaquin train per day that goes into Sacramento. To get from the other San Joaquins, you have to get off in Stockton and take an Amtrak bus about an hour into Sacramento..
Among the things to see in Sacramento are Old Town Sacramento including the California Railroad Museum and the state capitol building and beautiful grounds.
There are several Capitol Corridor trains per day from Sacramento to Emeryville with the bus connection over into San Francisco.
While in the San Francisco area, you may want to go to visit Muir Woods to see some great Coast Redwoods which are different from the Giant Sequoias that you will see in Yosemite.
If you wanted to go directly from Los Angeles to San Francisco bypassing Yosemite, try the Amtrak Coast Starlight train from Union Station and arriving late evening in Emeryville to use the bus over into San Francisco.

Yes you can drive from LA to Yosemite, see my earlier post.

Here are some ideas to help you plan your visit to San Francisco.
https://www.fodors.com/community/uni...ations-356478/

Stu Dudley