I was camping there around this time last year (I think around Feb-March). Even though it's not summer time, you still have to be prepared for temperature extremes. I camped out up in one of the higher campgrounds, and when i woke up there was a little bit of snow on the ground. Less than an hour later, I was down in the valley (at the aptly named Furnace creek) where it was 85 degrees, and still getting warmer. Next day I was exploring one of the old ghost towns on the outskirts of Death valley, and it was snowing hard again. So don't be surprised by 50-60 degree temperature variations.

Hat, water, sunscreen, water, lip balm, water, and warm clothes are a definite must for this time of year. Oh yeah, I think I forgot to mention water. Sunglasses and a bandana were nice to have standing at the top of Ubehebe, because it was really windy up there. Depending where you're going, there's probably going to be little or no shade, and the air is pretty dry. It just sucks the moisture out of your skin. Other than that, it's a great place. It's probably fairly busy right now, and as long as you stay where most of the tourist are, you probably aren't going to have much of a problem. Oh yeah, most everything in Death Valley is pretty spread out, so you'll probably be spending a lot of time driving from one place to another, so prepare accordingly

If you're planning on visiting the Racetrack, then you'll need a lot more stuff. The easiest road leading there is a rough 30 mile dirt road from the main highway, so don't get stranded like that family did last year and had to walk out. But it's definitely worth the drive.