In reply to Adrien:
> Yes we're going there in May specifically because the waterfalls in Yosemite are supposed to be spectacular Hopefully crossing the Sierra Nevada won't be too much of a problem, it'll be the end of May then so there's a good chance the Tioga Road is opened. If it's not I'm sure the road to South Lake Tahoe isn't too bad in terms of scenery.
> Is the coast that bad that time of year though? We're planning on spending a couple of days between San Francisco and Monterey. Don't care if the weather isn't optimal for sunbathing.
> From what I've read here and elsewhere it seems Bishop is a better bet than Joshua Tree, both in terms of weather and grades (possibly in terms of scenery too). Let's see how many days I can convince my friends to stay there
Waterfalls were good at the end of May. There's good info online about the opening times for the passes. Coast may be a bad idea- there's a cold water current (Catalina current?) that brings fog/rain/drizzle to California in May. JTree was hot in May - no good for climbing your hardest grade, but you're on holiday so that doesn't matter.