For nature & scenery, Mt Fuji / Lake Kawaguchiko (day trip) delivers.
On a clear day this is the Fuji shot — the mountain reflected in the lake, the Chureito Pagoda framing it, ropeways and a flower-lined shore. The brutal catch: Fuji is shy and clouds over often, especially in summer, so a bad-weather trip means a long ride to see nothing — go with a flexible day and a forecast.