LIFE or DEATH WARNING: Be overly prepared for anything, this remote desert land can be a killer.
"A map in that case may have been a lifesaver for them."
Don't plan on seeing all this vast beauty in one trip. No way possible, unless you have a year off to explore. Off-roaders in Panamint Valley, mining camps, ghost towns, cool geology, and discovered the Manson hideout cabin. Saline Hot Springs and sand dunes, stargazing, castles and craters, palm oasis golf course, canyon hikes, abandon mines, stone cabins, plus so much more. Plan on spending a week or more, with 4x4 back routes - if your time is of leisure.
DUH: Death Valley is the hottest spot on the Western Hemisphere. It is common in the summer for temperatures in the valley to reach 120 degrees F (49 C). The average July temperature in Death Valley is 101 F (1961 - 1990). If you want to visit in summer, stay along main roads. Realize that real dangers arise on the back roads, where cell phone coverage and real help is unlikely (for weeks). Heat and this environment can kill, even if you so have a GPS, air conditioned SUV and water.