Along the Izu-Hakone train toward Shuzenji, you could stop at the Izu-Nagaoka station to see the Reverberatory Furnaces, which were built in the 1850s, and recently awarded World Heritage site status. These furnaces were built for casting Western-style iron cannon to strengthen Japan’s defenses in the Edo period. It’s a 30-minute walk from the station. Opened to visitors year-round, except on 31st December and 1st January.
Next to the reverberatory furnaces, you could pick green tea in summer. Or opt to pick mikans in winter. From the Izu-Nagaoka and Nirayama stations, you could head to one of the many strawberry farms to pick strawberries from mid-December until early-May. Pay a fee to pick and eat as many strawberries you can for a limited time. There are also many onsens and hotsprings in the ryokans in this area.