Unless there is an actual storm happening during your ride, those routes of Dan's aren't really cold. Even up at the top (Angeles Crest Highway) you can expect a typical February day to be in the 50's. It's warmer down below, of course. I've ridden right past snowbanks and people trudging over to the ski lifts in 55 degree weather in February up there.

Actually, Joshua Tree is likely to be every bit as cold as the mountains this time of year. Beautiful riding, though.

You'll likely want to rule out coastal rides, since the coast is a good 3-4 hour drive from Joshua Tree.