So I'm in NYC, and I want to get to Babylon for the 100 mile. I don't have a car and I'm not allowed to bring my bike on the train that day. How do I get to Babylon?

Coming back means another layer of complexity - instead of two possible drop off points for the trucks you now have four and more chances of something going wrong.

Penn is a good place to start - you're forgetting that many people come in all over and it's a large transit hub that people can get to and equidistant for most people in the city. Also easier to load large amount of people on because it's the last stop. For someone in Brooklyn getting to Jamaica would be hellish by subway.