San Diego to Borrego Springs.

90 miles, roughly 2 hours and 10 minutes. CA-78 east through Ramona to Santa Ysabel, CA-79 north toward Warner Springs, then Montezuma Valley Road (S-22) east. The road descends 3,400 feet in 11 miles into the Borrego Valley.

Dudley's Bakery (Santa Ysabel). Mile ~50. Famous date-nut bread, jalapeño-cheese loaves, coffee. Easy detour off CA-78.

Julian. 7 miles off-route. A historic gold-mining town that became California's apple-pie destination. Skip on a busy weekend, recommend on a Tuesday.

Ranchita. A general store and not much else, but it's the last place to fuel up before the Grade.

Montezuma Grade Overlook. A 30-second pullout with a 50-mile view across the Borrego Valley. Stop.

• Cell signal disappears around Ranchita and stays spotty in Borrego. Download maps offline.
• Gas is cheaper and more reliable in Ramona than in Borrego.
• The Grade has tight curves and is shared with motorcyclists on weekends. Drive it relaxed.
• If you're prone to motion sickness, take the descent at half-speed.