The area around the source contains several well groomed trails through fairly dense forest. There are a couple of courses one can follow, neither of them very long, but all in all... it's an extremely nice place for an afternoon walk. As it's along the Himekawa Cycling road, it's an ideal place to take a bit of a break before perhaps continuing on to Aoki Lake or turning around back into Hakuba proper.
The parking lot for Sanosaka, is about 10 minutes drive from the hotel. If you are coming into town from Matsumoto, you'll see the Sanosaka Ski area and parking area on your left as you come down the hill from Lake Aoki. Entrance to the park itself is only signed in Japanese, but enquiries at the Sanosaka Tourism Center should get you pointed in the right direction.
Information (in Japanese)
