After getting down from Mount Tsukiyomi, I walked the Ikoi trail (奥多摩湖いこいの路). It is a mostly flat path that follows the south bank of Lake Okutama from the Ogouchi Dam to the Yama-no-Furusato Village. The autumn colors were quite nice in the sunset. Very relaxing after the mountains! Although I only did a short section, the whole trail takes about 4 hours.
After the Village, the Ikoi trail gives way to the Lakeside Path (湖畔の小道), which ends at the floating Mugiyama-no-Ukihashi (麦山の浮橋) bridge (aka Drum Bridge). The bridge takes walkers across the lake, next to the Ogouchi Shrine on the north bank. However, it is sometimes removed in case of drought (this blog should have some up-to-date info on closures).
Above, the floating bridge.
Above, looking west.
Above, looking east.