Portland, Oregon is great
My dad grew up there and we visit a lot and it's a city, there's beaches nearby, mountains nearby, forests nearby, and if you drive out east it's countryside-ish
Tokyo. I lived in Fussa and 20 min one way and I'd be in downtown Tokyo, 20 min the onther way I'd be in a quaint mountain village/city, with beautiful nature and parks! And there is also a bay about 30/40 min away! Only problem is you need to have a very, VERY well paying job to live comfortably in Tokyo, not that groceries are expensive, but rent is astronomical.
My dad grew up there and we visit a lot and it's a city, there's beaches nearby, mountains nearby, forests nearby, and if you drive out east it's countryside-ish