One of the great things about Japan is that, no matter how obscure your interests, there will be groups and clubs that support it.
Like steam trains? Ferry boats? Fishing for BIG fish? Fishing for TINY fish? Raising beautiful fish? Hiking? Cooking in infinite permutations? Climbing? Go? Variations on gardening? Bridge? Competitive chrysanthemum growing? Watercolors? Saxophone practice with strangers in parks (since this instrument, in particular, cannot be played into head phones for non-neighbor-annoying practice sessions)? ANYTHING you can think of, there will be other people who enjoy it and all you have to do is seek them out.
Many of a subset of MY people, the boat-ride loving types, rode ferries from Nagoya to Tomokami and back with me last week, taking advantage of the Silver Week holiday despite two typhoons and lots of pouring rain.
A large group brought their motorcycles. One of my cabin-mates, I saw -- recognizing her from her helmet -- has a particularly slick BMW, street-legal but with nice fat tires. When we boarded in Tomokami, in the pouring rain, the motorcyclists were all just soaked and miserable looking. Not a week for motorcycling, though some days were nice enough. By the time we returned to Nagoya, it was lovely out, of course, and they roared off, dried, laundered (there is a coin laundry on board) warmly soaked in the Grand Baths (Sentos with sea views; everybody loves them) and well fed (the buffets in the restaurant were sumptuous, even for me, though some people prefer to bring cup-noodle type provender) and seemingly quite content.
A sister-ship of the ferry I came in on, possibly the one I went out on. There are three that ply this route in turn. They are not identical, but pretty close. They are cargo ships, but also have some room for boat-loving passengers, including campers, bikers, car drivers and more, in addition to the people who drive the container-carrying trucks that form most of their cargo.