We stayed at the fairgrounds in Santa Rosa CA a few weeks ago, basic camping - full hookups, no cable or WIFI. It's about 45 minutes to Sonoma. Also stayed at the Napa Expo campgrounds, it's in Napa Valley but about the same distance to Sonoma. I preferred Napa.
Some good things to see in the area - Point Reyes National Seashore, Muir Woods - Giant Redwoods (don't try it on a weekend). San Francisco is within an hour or so depending on traffic. Golden Gate, Alcatraz, etc. Of course a LOT of great wineries in the area. Let me know if you need suggestions.
2016 Roadtrek CS Adventurous
2015 Jeep Wrangler Unlimited