No comments from me as I've never been to the islands.
Can anyone please tell me whether Numazu, Shizuoka city, or Hamamatsu is worth a night's detour? We're spending a weekend on the Izu Peninsula and I'm having some fun researching and putting together a rough itinerary for that now. I know that Shizuoka is supposed to be a fantastic regional food draw but I wonder if there's anything to really see/do/eat that would absolutely be worth an extra night outside of Tokyo? I'm guessing the answer is probably no, considering we're already spending two nights in Shuzenji and plan to explore the peninsula. I'm thinking more in terms of food than anything else, I guess.