Best Tokyo area for cafes, parks & exploring?

Hiya, I'll be visiting Tokyo for 5 days in mid-October, solo traveler. I love fast-paced, big city environments, so I was thinking of staying somewhere in Shinjuku at first. However, I thought that I can look somewhere more laid-back and scenic, as I'm also very big on exploring local trendy coffee shops, parks, etc. Can someone recommend areas to stay that are both well-connected but also allow for a nice lil morning walk?