It's a nice place to enjoy nature in a well-maintained garden. There are paths, bridges, a nice cafe for coffee or a fruit drink, many different kinds of plants. It's a bit far, but a bus leaves from Karuizawa Station and returns. Be sure to check the times if you take a bus. The cafe can call a cab if you ask. Look for the huge koi in the lake and moats. Enjoy the lush vegetation.