Washington County is terrific. You can park in Schuylerville (Saratoga County) in the Hudson Crossing Park at Champlain Canal Lock 5. Off the back of the parking lot is a foot/bike bridge that takes you over the Hudson and dumps you right into beautiful farm/Amish country, gravel and dirt roads all over the place along with quiet paved roads; and the one state road that goes through has a very wide shoulder. A friend and I did one of our favorite loops over there just a couple days ago and as usual, there is hardly any traffic. There’s a small lake - a pond, really, called Summit Lake that is pretty to ride around, and Cossayuna Lake just a mile or so away. Not a single gas station, market or anything else around though, so the water and clif bars are on you.
Lots of good stuff here in Saratoga County also, send me a message if you want some other info. But you can’t go wrong over in Washington.