Air, I must have been shadowing you on Saturday because I did the same Manhattan loop finishing around midnight. I agree with you, why not cycle in the rain, especially when it's warm out. We buy all this fancy wind proof, water resistant, quick dry, wrinkle resistant, kiss me quick clothing and so why not use it for what it's made for.
I can't figure my way around the upper east island. It's confusing and not well marked. But the night ride along Swindler's Cove at night was down right breath taking...until about 155th street and the honey moon is over. I couldn't find my way back to the water until 116th Street. I spoke to some kids there and they said I could have come in at 125th but that there was a bunch of rocks and glass along the path up there so I didn't back track to check it out.