Keep an eye on the Siskiyou Mountains if taking I-5 South. I never heard of them until I moved West..
Interstate 5 passes through the Siskiyou Mountains at Siskiyou Summit, located just north of the Oregon/California border, and just south of Ashland, Oregon. Siskiyou Summit is the highest pass on Interstate 5, at 4,310 feet (1,310 m). This pass is one of the most treacherous in the Interstate highway system. The California side has a more gradual ascent/descent, but on the Oregon side of the pass (the side which is more hazardous), the freeway gains (loses) 2,300 feet (700 m) in elevation over a 7-mile (11 km) stretch of freeway. In addition, the pass includes several hazardous curves, and is frequently hit with bad weather (including snow, ice, and fog) during winter storms. During winter, it is common for the highway to be closed one to four times by transportation authorities due to hazardous conditions. The speed limit is 55 miles per hour (89 km/h), but lower limits are set for larger vehicles.