I've done a supported trip between xmas & new years that starts in san diego - pine valley - warner springs - palm desert ... (then loops back to san diego).
That tour is put on by the san diego youth hostel (HI-USA), they might be willing to share route maps.
Road conditions are mostly good. Traffic by the salton sea is not a problem, although that road does have a small shoulder. it can be very windy.
I haven't ridden from palm springs up to the part (through morongo valley) but have driven it a lot - that would be a scary ride. It's a big up-hill, curvey, with lots of fast traffic and not much shoulder. Dont' know about the souther (cottonwood) entrance to the park, I imagine that would be better, but quite a long ride with no services.
I've also spent a good amount of time in joshua tree in december-february. if there is no storm, you are good for weather. if there is a storm, it can snow in the park, as well as the passes around julian. expect wind in any case. it regularly gets colder than freezing in the park at night. you can also have pleasant daytime temps. I was there for 3 weeks this year (feb) and rode a bunch.
expect the most specatcular sunrise/sunsets anywhere. you should go to jtree, it is special.
it's true there are limited services in the park - pit toilets, picnic tables, fire pits, NO water - but it's a short ride to the town of joshua tree/yucca valley. also, the park is populated with rock climbers all winter, and they (we!) are super friendly. if you want to hang out in the park, it would be really easy to ask someone to help you get some water, or to tag along on a store run. Hidden Valley campground is the place to hang with the climbers. I would be seriously shocked if you couldn't score a day or two of water just with a short friendly walk around the campground.
there's a campfire somewhere every night.
The Yucca Valley/ Joshua Tree area (rock climbers, hippies) is much nicer than the Twentynine Palms side. (military, meth-heads). Eat at Crossroads Cafe if you can afford nice food, Santanas if you need to go big and go cheap. Showers $3 at Coyote Corner.
have a great ride!!!
This message was edited by valygrl on 3-29-07 @ 9:35 PM