Deb Ford's favorite ride
A "flat-ish" ride that begins in Napa.
My favorite 'flat-ish' ride is from Napa to the Jimtown Store. It's a 90-mile out and back that takes you through the Napa, Knight's, and Alexander Valleys. There are some small rollers on the Silverado Trail, a short climb out of Calistoga, and more small rollers thru Knight's Valley. It's gorgeous all year round, but spring and fall are particularly spectacular.
This ride can be shortened or lengthened in a number of ways. There are great bakeries, delis, or a couple of brewpubs at which to stop and enjoy the treats of the valley.
Oh. Almost forgot. You may cycle past a winery or two.
Here's a link to the ride: http://ridewithgps.com/routes/301440