A few final thoughts:
.
Skip the Circle Line. It is time-consuming, and parts of it are inevitably very boring. You’re not really seeing New York.
The Metropolitan Museum of Art is totally free since it is on public land. I would go, even though it can seem overwhelming. Go to the second floor and see the Rembrandts, and then whatever else takes your fancy, or just have lunch there and then go somewhere else, but do see the Rembrandts.
the MMA is FREE????