From SF, I vastly prefer 99 over 5. I also take my time. Here's a suggested route, complete with recommended RV parks. Leaving SF, take 120 over to 99. You'll pass a Bass Pro Shops in Manteca. If you've never been to one, and are an outdoor type, plan to stop for a few hours. Castle Air Museum RV Park in Atwater is where I'd stop for the night & check out the planes. (Haven't been, but will next trip!) Down 99 to Bakersfield. Couple of great parks. Use Bakersfield RV Resort and enjoy a great dinner at their on site restaurant. Take 58 to 395. But check weather, especially for wind in the Tehachapi & Mohave areas. 395 to 15 to Temecula. Spend the night at Pechanga RV resort. Time your travels to SD around commuter traffic.
We retired out of Temecula. Did biannual trips to Redding. This is the optimal route.
