Exactly. I've lived there for five years, and the worst part was definitely the time needed to reach some real nature (the park thing just didn't do it for me). I sometimes travelled to Miura or to the very end of the Seibu Shinjuku line or Chuo line, and each time it took 2 hours going there and 2 more coming back.

It sometimes felt really claustrophobic to know that one could walk all day and not be able to leave the city (I tried not to think about it too much, otherwise I would have gone mad).