Mike,
Easy trip. You won't be the only person walking around with a camera and tripod. Like everyone says, bus, subway, map of central park would be good. Give me a budget and I'll try and find a sherpa, day,1/2 day, but still $50 or so for 1/2 day, maybe $100 for a full, 8 hour day.
For you, I would find a bunch of iconic shots and then travel there for 3-4 seasons and retake from the same place and then sell them as a grouping. Planning is very important, if you want to cut down on the walking around and looking.
Rich