A ham radio programmed to the local repeaters. Note that you can legally transmit without a license in an emergency on a repeater frequency. A UV5R handheld radio can be had for less than 25 bucks and programed with free "Chirp" software. It does take some effort to get it properly programmed. There's a small learning curve. I program in all the local repeaters, GMRS, MURS, forest, marine and weather frequencies. I carry one in my motorcycle because it works where cell phones don't. You could use it as a GMRS radio. It's technically not a legal GMRS radio but the FCC is not going to kick in your door if you did. I keep two in the van that are always on the charging base.
HAM Radio in DV does not work well on the valley floor. I have spent a few trips in DV (Furnace creek) attempting to access other transceivers with absolutely no luck. APRS is useless as their are no Digipeters. My money is on a SPOT device. However keep in mind DV now has roaming cell service that covers the valley floor fairly well.
For the van
1) Install tow hooks & upgrade your tires. Dually tires tend to pick up rocks between the rear tires which could be a major problem. DV is all rock, everywhere.
2) Pack a 20 foot HD tow strap. Not rope!
3) Avoid washboard roads. Take your motorcycle instead. Washboard is the fastest way to destroy a vehicle. West Side Rd can get soft sand and tons of washboard, so if you plan on getting into Striped Butte Valley (up warm springs road), access it from the south entrance to West Side Road. Virtually no washboard. 35 56.26N 116 42.28W
4) Stay off the shoulders, particularly if you are doing a three point turn.
5) Water, Food, & Shade.
6) Have fun