The trail is nice and flat, but can be snowy/icy and slippery. It's a nice and easy walk along the forest. In winter, you definitely need to be dressed warmly. The temperature was freezing when we visited in mid-Jan. 2016.

The nearest train station is Yudanaka Station, little over an hour by Nagano Electric Railway train from Nagano Station. From Yudanaka Station, it's about 15 min. by car/taxi to the park entrance. A day trip from Tokyo is possible, but I highly recommend staying overnight at a nearby onsen (hot spring).