I'll 3rd Yosemite. I did almost the same road trip 2 years ago. And it sounds like we hit the same things that mlord suggested. Yosemite is the most spectacular National Park in the West, IMHO. And the Bristlecone Pines are fascinating. Until recently they were on record as being the oldest living things on Earth. I don't know what showed them up, but it has to be damn old (I think it was some kind of bacteria). They used the rings of the Bristlecone Pines to calibrate Carbon-14 dating if that gives you any idea how old the trees actually are. The drive from Yosemite to Las Vegas is not rough at all. There are some curves and a great deal of elevation change, but the curves don't even compare to Hwy 1.

Anyway, after having done both the coast trip and the Yosemite route, I'd recomend the Yosemite route. The sight of Bridal Veil falls, El Capitan, and Half Dome all at once is just amazing.

- trs