Japan is only the size of California, and you can take quite a few decent day trips from both Tokyo and Kyoto. On my last visit in June 2012, I used my JR Pass to take a day trip to Matsushima on impulse. I didn't get back to my hotel in Tokyo till nearly 11PM, but I had plenty of time to explore Matsushima and even a bit of Sendai.

Personally, I like packing and unpacking as little as possible, and frankly, ryokans can be limiting. It's not exactly a matter of "you've seen one, you've seen them all," but after a while, you may be eager to sleep off the floor, take a shower, sit on chairs, and have coffee, rolls, and eggs for breakfast instead of green tea, miso soup, and rice with nori. You may want to choose what to eat for dinner instead of eating the ryokan's one or two meal options.

There are many fine Western-style hotels throughout Japan, and if you want to make a point of eating Japanese food, you'll find that most large hotels have both Western-style and Japanese-style restaurants on the premises.