pjh wrote: Well done on the Gs. If it feels good to you, then it's right.
As to the CA coast there are loads of places. You don't say how long you're going for, and that's one of the key factors. I'd try and avoid an itinerary that involves trying to cram everything in, as you then end up just driving, stopping, driving again...
Well done on the G’s – that sounds an amazing price especially for four

!
Having driven 2,384 miles across California, Nevada and touching Arizona in 13 days this year (actually 10 days of driving as we had three full days in Vegas

) I'd agree with pjh - although our tour was to deliberately light touch a number of places and next year we have 14 nights with a number of two nighters planned.
In May we drove up the Pacific Highway from LA to Carmel, with one night at San Simeon – chosen for it’s proximity to Hearst Castle and price at the time. Hubby and I now feel that we would have preferred to pay the extra and stay at Cambria.
The drive from San Simeon over Big Sur was around 90 miles, which Google Maps will tell you is around 2½ hours driving (before stops). It was a Sunday, and there was a bike race on, the road is single carriage way and twisty – driving north we were on the right hand side of the road with the cliffs on our right rather than the sea. I would guess that we took 5 to 6 hours to drive those 90 miles - and we didn't stop at every view point and only really walked at McWay Falls which was hardly strenuous!
We also drove from Carmel to Mariposa (about an hour outside Yosemite) - this was around 168 miles. I can't imagine it will be an issue on the main roads and highways but there may still be snow around Yosemite dependant on how this winter goes - winter 2015/16 was an El Nino winter and the roads across Yosemite were still closed when we were there in May.
You don’t mention how long you were thinking of staying in Vegas – I’m sure you’re aware but don’t forget your 17 year old can only walk through the casino areas and will not be allowed to drink or gamble, and your 21 year old will be ID’ed everywhere
We drove from Vegas to LA along the I-15 and it was a horrible drive - five hours on four lane highways with speed-unlimited HGVs under and overtaking - and we weren't going slow either! Hence we are seriously considering flying next year - although the recent outages at South West and Delta are making me think about extending the car hire as a contingency – just in case!
You could drive from Vegas to LA via Death Valley and break your journey there - but it is still 4.5 hours from Death Valley to LA.
Our current thoughts for 2017 are:
Flying into SFO and spending the first night near there – Pacifica/Half Moon Bay area
spending two nights in Carmel/Monterey (whale watching trip planned one morning)
Cambria or Paso Robles for two nights (wine tour planned for the in between day)
Santa Barbara for a night
two nights in LA
flying/driving to Vegas for six nights.
I hope this helps!