10 persons "lifetime" trip around San Francisco - Los Angeles - Las Vegas / 2 weeks

Hello everyone there !
Just discovered this amazing forum this morning, and i know this is probably the best place to find the answers i'm desperately looking for.

Here's my situation :
We are a bunch of 10 French guys & girls coming to San Francisco on August 8th, 2011. We're leaving from SFO on August 22th.
Most of the people here are "town people" and not especially "land & forest people", and that's where the trick is. They prefer to spend time on all Californian famous beaches (i love that too, but not as much as they do)) rather than spending days walking in your magnificient national parks.
That's why i've planned 3 and a half days in SFO and 2 1/2 in LA. We've planned a trip around SFO, Los Angeles & Las Vegas but i'm trying to fill in the gaps between these three stages.
We're staying at SFO until August 12th in the morning, spending the night in Santa Barbara, and then staying over the weekend until Tuesday, August 16th in LA.

And here's where you can help me : leaving from LA, what are the must sees, and what is doable by car from LA to go to Vegas ? Is a three-day ride from LA going from Yosemite and Death Valley to Vegas something irrealistic ? Which parks are doables from Las Vegas in one or two days trips ? For us, Las Vegas would be only interesting to spend two nights there, but i want to optimize everything.
I know two weeks is far too short to see everything but you're more experts than i will ever be, and i'm trying to know what is unmissable and what can be left for a second trip, maybe with more "adventurers" guys with me.

Thanks in advance for your help and please forgive my patchy English !
Romain

Welcome!

If you have only 3 days to get from LA to LV, I'd go from LA to the Grand Canyon then to LV. You could then make it a 2 or 3 day trip back to SFO through Death Valley and Yosemite.

Wow, that sounds clever and well-packed ! Thanks a lot !