During Christmas break of 1987 I took a mountain bike ride around Death Valley, California. I'd never want to go any other time. They say the temperatures normally get up to 110 degrees in the summer; it was hot enough at Christmas time! There are facilities all around the park so water wasn't a problem and there's a couple of campgrounds in the park (camping is prohibited anywhere else). Bring some money - they charge a fee to get into the park and for camping. It ain't cheap!