Yosemite is probably already booked out.
August is summer and peak season in the US. The main tourist traps will be extremely busy.

 

Then it will be booked out on April 16.

 

Awesome part of the world to go camping. Do plenty of homework, I just did some quick googling.

You'll love Yosemite so much that you may want to stay longer than booked....so

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

 

Stay at Tuolumne instead. Its colder but August is mild. Or there are roadside spots at El Portal. Crane Flat is also an option.

 

Answers to some questions-

Dump stations with potable water are common at interstate rest areas. Otherwise, National and state parks will always have the same so it’s easy plan after a few days at more rustic campsites.

Safe? Do you mean from crazy gun toting Americans? For the most part yes. Weapons are not allowed in national parks, and visitors tend to be more sane.

If you can travel the latter part of August the crowds should diminish since lots of schools start then (though I could be wrong about California...I’m from Seattle).

I favor Montana, Washington, And Canada for camping (much less crowded), but did find Yosemite scenery amazing. Some years back did a two week trip from Seattle mid/late August to Lassen peak (drive thru), lake Tahoe (beautiful), June lake/Mono Lake (cool walk to non- commercial ghost town nearby), and Yosemite. Loved every bit of it.

Also consider Utah. Again several years ago did 2.5 weeks touring Utah state parks in September which is one of my all time favorite trips. Mostly Europeans that time of year.

PM me if you have more questions. I grew up camping in the Rockies in an airstream with my parents, and camped the west in a travel trailer for years with my own kids/family.

 

Bodie might be the old gold mining town you're talking about. An hour or so drive from the eastern entrance to Yosemite, and then plenty of walking once you get there. Definitely recommended.

 

Bodie was awesome. Did it in October last year and the day we visited they had a night photography tour on and I didn't know about it They only have them every a couple of times a year too

 

I saw some very scary footage of the drive in to Yosemite in their peak times. Go early - like really early before 7am if you have to. The traffic jam was bad and then you drive around for hours if you can't find a park. We went in the fall so we didn't have those issues.

 

We did an RV trip which included Yosemite in 2012 (2 families, 4 adults and 4 kids aged 7 to 14).
We stayed in the RV park at Indian Flat. It was very basic but adequate. We caught a public bus into Yosemite each day from the lodge/motel/resort next door to the RV park. Next door had a restaurant which we had dinner at one night. The RV park also had an agreement with next door that we could use their pool. It worked well for us.