There are many temples and shrines in this area; the whole of the Kii peninsular all the way from Kyoto to the sea at Kushimoto in Wakayama, along the Kumano Kodo, it would take a lifetime or more to see them all let alone visit and learn something about them. Here in the area around Yoshino thousands of people come to see the cherry blossom in spring. For more information on the most famous and popular sites, please see the Wikipedia page:
https://en.wikipedia.org/wiki/Sacred_Sites_and_Pilgrimage_Routes_in_the_Kii_Mountain_Range
For more information on Yoshimizu Jinja, please see their website:
http://www.yoshimizu-shrine.com/
The cache can be found outside the main gate to the shrine.