The Hakone loop is something I recommend to visitors for whom covering long distances by foot is a concern or a problem, that might include those with young children and/or elderly relatives.

If your companion isn't particularly energetic but likes to sit and see changing scenery and have the chance to exchange a few words with a succession of fellow visitors (mostly Japanese tourists), then the Hakone loop is ideal. Unchallenging and restful yet gives the feeling you have been very active.