Check out the YARTS bus routes and avoid driving a vehicle into Yosemite. The YARTS bus drives right past all the cars waiting to get into the park and has a designated spot to drop off and pick up passengers. There is a free bus service within the park once you get there.
There is YARTS bus service from Merced and from Fresno (Google it). Does Southwest have service to Sacramento? That would be the easiest airport to get to Merced with a rental car.
After seeing Yosemite and Sequoia, you will have seen your fill of huge trees without seeking a State park.

>>then going to mammoth lake for one day /night then just going to kings canyon for a day/night ( mostly to see Canyon )Then go back to lax. ( we need to fly from somewhere southwest goes) does that make more sense ?<<

No :( Simply not doable. You can't get from the east side of the Sierra (Mammoth) to the west side (Seq/KC) There are no through roads. So you would have to drive all the way around through Bakersfield, and that is nearly 400 miles. . . . UNLESS you go back north and across Tioga Pass through YNP and south to Seq/KC -- which is about 300 miles and more than 6 hours driving and is totally back tracking.

Southwest flies in to SMF, OAK, SJC and SFO so you can fly into northern CA, do Yosemite, then Seq/KC and fly home from LAX or BUR or ONT.

No, you do not want to take YARTS from Merced or Fresno - that would take FOREVER -- you can though take YARTS directly from the stop in front of Yosemite View Lodgein El Portal.

day one-drive from sacramento or lax to yosemite,
day 2 and 3 yosemite
day 4 drive early ro SEK and do long day thereand either stay in three rivers or drive s few hours to be closer to next stop
looking for recomendations. rather then go back to SEK in traffic (no lodging in SEK that meets our needs) what should we do next on day 5/6
need to be somewhere in california by friday afternoon.

did not book anything yet so could also do something before Yosemite. thanls for all your help

I would do Mammoth or SEKI but not both with the amount of time you have. Either location has enough to fill 2 nights. I don't think you have time to drive to SEKI (4 hours from Yosemite), drive to the bottom of the canyon, see the sequoia groves and tour Crystal Cave in one day. What's your lodging criteria?

I thought yosemite was closer to SEKI but if we went just for a day I would have to miss crystal cave (you have to book in advance in person anyway)
If i go to mammoth would it make the most sense to fly back from vegas? basing that question off the earlier reply about the ways the roads go so guessing would be very long to get back to california is that correct?

as far as lodgong we really need a place with a fridge since we will be bringing our food due to special dietary needs.
(I know I should have booked all of this months ago) thanks again

Our room at Wuksachi had a mini fridge. I believe the rooms at John Muir Lodge do as well.

Mammoth is still in California and Vegas isn't really any closer than LA or the Bay Area. I thought you were going to Vegas for some other reason (other than just to fly back). Reno may be the closest airport that Southwest serves. When in June are you going? Last year Tioga Pass didn't open until June 29th https://www.nps.gov/yose/planyourvisit/tiogaopen.htm but that was a big snow year and we haven't had as much snow so far this year. There are other routes across the Sierras as well.

>>but if we went just for a day I would have to miss crystal cave (you have to book in advance in person anyway)<<

Sequoia is not a day trip from almost anywhere. Neither is Mammoth.

Yosemite View Lodge has kitchenettes.

Cedar Lodge (also in El Portal) has fridges.

i already booked Yosemite view lodge. my lodging concerns were for SEKI because i was told not to book in 3 rivers due to traffic and there is no availability inside park. later tonite i am going to look more closely at mammouth may just decide to go there two days instead of SEKI. any recommendations of nice lodging there? also just curious where all you guys live? we seem to be in different time zones, I am on eat coast and love that I wake up to your helpful advice. thanks again.

In addition to Mammoth, look at June Lake for lodging.

We we are locals.

Have you said when in June? If the beginning of the month, it is more possible that Tioga Pass won't be open. If that's the case you can't get to Mammoth from Yosemite except going north all the way to Tahoe and south to Mammoth OR south to Bakersfield -- both are a looooong slog.

If Tioga is open, sure you could visit Mammoth -- but we won't know until late April or early May how much progress they are making clearing/repairing the road, and when it will open. This year's snow season started out very light . . . but there were big storms a couple of weeks ago and and a LOT of new snow is expected this week. Tioga has opened as late as early July but that is exceptional. Most years it opens late May or early June. But with late spring storms a late opening is pretty normal.

So you will have more certainty doing SE/KC . . . and if accommodations in the park is unavailable, there is nothing at all wrong with staying in Three Rivers.

The downside of Three Rivers is the construction this season but you could try to time your drives to avoid lengthy delays. Book a back up and keep checking for in park cancellations as they happen often.

I stay with friends in Mammoth but there's no shortage of accommodations there. There are a lot of condos which might work well for your needs. Friends who stayed at Juniper Springs recently liked it. We do seem to be getting more precipitation late this season.

>>We do seem to be getting more precipitation late this season.<<

They are predicting up to eight feet of new snow this week . . . with another series of cold storms next week.

>>Book a back up and keep checking for in park cancellations as they happen often.<<

I agree. Three Rivers isn't perfect - but it is convenient to the parks and if you book something refundable/cancelable there and keep trying there is a great chance you'll get a place in the park.

>> They are predicting up to eight feet of new snow this week<<

Holy @#$%! I didn't realize it's that big of a storm.

not going til mid june-right now i am booked in yosemete view lodge for first three nighyts then in three rivers and mammath for next two nights so i guess i can decide at a later point and keep checking in park for SEK. thanks

What are the cancellation policies at Mammoth and Three Rivers? If generous, you could keep both until nearly the last minute . . .

BUT Mammoth and Three Rivers make a difference where you fly home from (and rental car drop off too).

Three Rivers is about 3 hours closer to LAX than to Vegas. Its only about 3.5 hours to LAX (longer in heavy traffic) and about 6.5 hours to LV. While Mammoth is about a 5.5 hour drive to either one. (if you fly out of Ontario

If it was me I'd bite the bullet and do Seq/KC and forget about Mammoth.