This nature walk from Hakone Botanical Garden to Togendai is lovely and easy. It takes about 2.5 hours and is best taken on a dry day. Highlights include Sengokuhara pampas grass, views of Ōwakudani sulphur plumes and the surrounding mountains, cedar and bamboo groves, some fish and bird sightings and ending at Lake Ashi. I recommend book-ending your walk with some time in quaint Sengokuhara and at Lake Ashi.
To reach the trailhead: From Sengokuhara (仙石原) head towards and past the Hakone Botanical Garden, take a right at the Japanese restaurant Fukufu, and follow the signs to Kojiri (湖尻). Note that the route is briefly residential, but carry on and you’ll find the trail head.