As a couple, Nikkō (day trip) works.
The lavishly carved, gold-leafed Tōshō-gū shrine complex set among cedar forest and waterfalls is unlike the restrained shrines in Tokyo — genuinely worth the trek for shrine and nature lovers. The catch: it's a committed 2-hour-each-way day, the sights are spread out, and autumn foliage weekends bring traffic and crowds.