Silverado trail is pretty, and quite flat. BUT there are a ton of FAST cars on it. Not to mention the winery crowd.

I would suggest going toward Pope Valley on Chiles/Pope Valley Rd. (Past Lake Henessey). You can do an out and back to Pope Valley and come back via Lower Chiles Valley Rd. or you can go up Ink Grade, which is a four mile climb - but nothing terribly steep. This is all on the east side of Napa Valley.

The store in Pope Valley doesn't open til about 10.

On the West side, you can go up Dry Creek Rd. which runs paralell to Silverado and Hwy. 29. That is a nice rolly road. On either side o fit is Mt. Veder and Oakville Grade, but Dry Creek itself is pretty flat.

Have fun!