I am traveling next week and I always try to find the hidden gems and local highlights of every place I visit. I would highly appreciate any recommendation from locals!
No place is really "hidden" - but there are some good sights in the area, aside from the obvious Ise Shrine.
Another big place is the Kumano Nachi Taisha with the famous Nachi waterfall - widely regarded as one of Japan's best. There is also Spain Mura which is a theme park with various roller coasters etc, and a hot spring is next to it.
CLoser to Kansai is Iga-Ueno, which is famous for its ninja history. It has a museum and castle, plus some other sights.
If you are going next week, you are getting close to the cherry blossoms season, and the finest place in Japan is at Yoshino in Nara, with over 30,000 blooming trees. You may be too early for its peak, but if you are flexible, it is a stunning place to see.