Directions to Sonora from SFO:

1. From the airport, head south on Highway 101 until you reach the interchange with Highway 92; this will be also be marked "San Mateo Bridge".
2. Take 92 East. This will take you over the San Mateo Bridge. Continue until you come to the interchange with Interstate 880.
3. Take 880 North. After a bit you'll see an exit for Hesperian Boulevard. Don't take that exit; take the next one. It'll say Highway 238 and something like Castro Valley.
4. Take 238 East until it merges with Interstate 580. Take 580 East towards Castro Valley, Pleasanton, Livermore.
5. You'll be on 580 for a long time. Like, 30 miles. Somewhere in here, shortly after you've passed Livermore and crossed over the Altamont Pass, 580 actually veers off to the right, heading south towards Fresno. This exit isn't real obvious, and if you keep going straight you'll find yourself on Interstate 205, which is what you want anyway.
6. Continue on 205 until it merges in with Interstate 5 North.
7. You'll get off 5 almost immediately. Take the first exit, which will say Highway 120. Other things it may say would be Manteca, Sonora, or Yosemite.
8. Follow 120 East. After 6 miles you'll briefly merge onto Highway 99 going north, come to a traffic light, and make a right turn. This keeps you on 120 going East.
9. You're now in Manteca, heading across the Sacramento Valley. You'll stay on 120 for the next 20 miles or so, passing through the town of Escalon, and then entering the town of Oakdale. In Oakdale you'll come to a major downtown intersection where 120 merges with Highway 108.
10. Turn left at this intersection. You're now going East on the merged 120/108, but at this point you no longer care about 120. Stay on 108.
11. It's about 35 miles from Oakdale to Jamestown. About 30 miles along, Highway 120 forks off going South to Yosemite, but you'll continue on 108 to Jamestown. Somewhere in here Highway 49 will also merge with 108, coming north from Yosemite. As you continue on 108, it's another 3 miles from Jamestown to Sonora.
12. As you approach Sonora, you'll see an exit for 49 North, Downtown Sonora, Stockton Road. Take this exit and it will lead you into downtown Sonora, ending at a T intersection where 108 meets Washington Street. Welcome to Sonora.