Could we maybe venture a leeetle bit beyond the bike path? Back and forth on a flat bike path would be fun, and the scenery is sweet along there, but once in biking mode I should also do a few hill repeats. Maybe up towards that picnic park up at Buena Vista winery? There's another bit of bike trail up there I think, after a short stretch of narrow road.
Bartholomew Park. Had to google a wine country map for the name.