There are a bunch of similar threads if you dig through the forum. Running routes are going to depend on where specifically you live in the city, but anywhere on the west side of Manhattan will give you access to the Hudson River path, which is something like 12 miles. You'll have an easy train ride to Central Park, where you can put together 10 miles without repeating, and a long train ride to Van Cortlandt, where you can run the CC course or hop on the Putnam Trail, which heads north for 30+ miles. If you've got a car you can drive up to Rockefeller State Park; you can also take Metro North to Sleepy Hollow and hop on the Croton Aqueduct trail. I haven't cracked 75 mpw, but not for lack of places to run. There are plenty of people in the city running very high mileage.