Causett State Park in Lloyd Harbor is beautiful. Nice paved winding, rolling paths that lead to a beautiful mansion and fabulous view of the Long Island Sound where you can have a picnic on a grassy hill.
I LOVE the Long beach, Boardwalk, where they play Volleyball and play concerts in the summer. Very nice ride and they allow bikes on the boardwalk with in bike lanes, I think it is 3 miles if you do one whole loop. If you get hot, jump in the ocean, or grab a drink on the boardwalk bar!