Base to use for seeing Yosemite in 3 weeks

Sorry, Monty-Rob -- I read that as a three week trip to Yosemite, not "the trip is in three weeks." In March, Highway 120 over Tioga Pass will not yet be open -- definitely stay on the west side.

Correct...coming first week of March not May...but thanks for info...

The OP is traveling in March. If it were me, I would want hookups also at that time... so I could run an electric heater.

If you are coming anytime after mid-May, I would split the time in two and spend about half of it on the east side! If you need full hookups, stay at Mono Vista in Lone Pine, at around 6000 feet -- the "commute" up Tioga Pass is not bad in a toad or a truck. If you stay on the west side down near Yosemite Valley, it can be pretty hot, and you look up from 4000 feet to the domes. From the trails that take off from Highway 120 in the high country, you are sitting among the domes themselves, and the air is a lot cooler:



Here is a blog post that may be useful -- lots of photos:

Tioga and Tuolumne Meadows area

We did two weeks at the Thousand Trail's CG(OK, so were members) just the same, it's a pretty nice CG. Not sure what they get for a site their but it is full hook-up, the CG itself is wooded with a small river running by some sites and it has all the services associated with TT. Have a Great time!

We stay at the KOA in Mariposa.

I have stayed at the fairgrounds in Mariposa and used it as a base for Yosemite. It is about a half hour away from the entrance to the park. A little more if traffic is heavy. Co-located at the fairgrounds is a very nice mineral museum.

We stayed at the Yosemite Pines just outside Groveland a couple of years ago and found it a good home base for seeing all of Yosemite - the valley, Tuolumne Meadows and Hetch Hetchy. I don't know how last years fires affected the campground but their website is still up so I guess they are OK.

When we go to Yosemite we use the Yosemite Lakes Thousand Trails on CA120. There is a CG side for non-members. It is about 5 miles from the gate, but it quite a drive to the valley. JMO

I have reservations at Indian Flat Campground just west of the entrance.
It's on Hwy 140.
Not sure how convenient it is for you.
Pat