The fast way from San Diego to Joshua Tree is about 2.5 hours of freeway via I-15 and I-10. The good way takes most of a day and crosses three completely different Californias. Climb into the oak-covered Cuyamaca Mountains to the gold-rush town of Julian, drop 4,000 feet down the Banner Grade into Anza-Borrego — California's largest state park — then skirt the strange, shrinking Salton Sea and slip into Joshua Tree National Park through its quiet southern gate.
Entering from the south means you drive the park in the right order: up from the low Colorado Desert, through the Cholla Cactus Garden, into the higher Mojave where the Joshua trees and giant boulder piles are. Here's the route, the stops, and a three-day plan. Let Wanderply build your version around your dates and narrate each stop as the landscape changes outside the window.