Enoshima is accessible by train, and the tour is free. I don't think the elevator is necessary if you can climb something like Yuexiu Mountain, but if you have children, they seem to be free, so you might as well buy an adult elevator ticket. There are several shrines and an observation tower up there. There's a place selling local snacks like bread and octopus cakes (which are also sold down below). I think there are hot springs and hotels in the island area, as well as open-air bars and cafes, which seemed quite nice. I took a quick tour, which took about an hour, including crossing the bridge. I wouldn't recommend expecting to see Mount Fuji; it was hazy.