maryellen, congrats on your distance. Do you know about Transportation Alternatives? They are a group in NYC that promotes biking and walking. Every Sept. they do a choose your distance charity ride. We did 55 miles last year, but you can do 15, 35, 55, 75, or 100. It's really fun, you meet some great people and get to see as much or as little of NY as you wish.
Here's the link:
http://www.transalt.org/calendar/century/index.html