I'm a big fan of Acadia National Park in Maine. The Park Loop Road with a side spur up Cadillac Mountain offer wonderful ocean views. I get out very early when there's very little traffic on the road and it's just glorious. If your wife isn't comfortable with that, Acadia has an extensive network of gravel carriage roads. These roads are car-free, generally not very hilly and the gravel isn't too sketchy if you don't have wide tires. I love the cycling there - mile for mile some of the best cycling in the Northeast IMO.