I’ve only used the subway and I can safely say it’s more than you need. Each station is no more than 10 min walk from each other. You can purchase a 1-week pass for unlimited travel- it’s more economical really, for just $31!
The best part about the subway is that it runs 24 hours a day- not surprising for a city that never sleeps (yes, Aeropostle at Times Square closes at 2am and WL and I went berserk shopping til 1am after our Broadway musical!)
The only downside is how the subway can be foul-smelling at times (read: pee) and you have homeless people sleeping through the night on the trains. But the train is also a place where you discover the soul of New York. You are met with musicians filling the otherwise quiet commute with lifting music.
I witnessed strange moments such as a girl taking a seat and opening her Peanut Butter spread and licking off her knife on the train. How about a really unusual sight- a black man dating a China woman? Or a lady with a non-functional eye i.e. she was wearing a fake right eye that doesn’t move, and I marveled at the wonders of technology. Other times, you may be faced with the odd chance of being harassed, like how 2 guys were sneakily taking photos of us in the train, or having your shoulder being mystically tapped from behind.
New York City is really easy to navigate- roads run parallel and perpendicular to each other. I’m not sure if you feel the same thing when you’re here, but each time I look at the streets, they seem to go to no end. Because the roads are flanked by buildings, it’s like seeing the light at the end of the road.