At the east end of Lake Ontario, cross using the Cape Vincent and Wolfe Island ferries to save some km and to get some nice views during the water crossings.
The Cape Vincent ferry from New York State to Wolfe Island Ontario is a private ferry so there is a charge, but you would have to pay to cross the Thousand Islands bridge anyways.
There is a pizza/burger place in Marysville for a quick bite to eat. There is also the Wolfe Island Grille with waterside patio for more upscale food and drink, and they often have live entertainment during the day on weekends. There are also a couple of ice cream places in Marysville as well.
The Ontario ferry from Wolfe Island to Kingston is part of Ontario's King's Highway system and is free, and it gives great water-side views of Kingston's waterfront, the Royal Military College, and Old Fort Henry as you come into Kingston.