I saw your reply in another question that lifts getting to happo pond will open on 1st june. I will be at hakuba on 30 May so, could you please suggest any activities or place for a short hiking.
One place that I recommend visiting for great views in Hakuba is the Hakuba Mountain Harbor at Iwatake Ski Resort. You can enjoy food and drinks at the terrace while looking at the Hakuba Sanzan mountains. The resort also offers mountain biking.
You can join rafting, kayaking, and canoeing tours with Evergreen Outdoor Adventure. They also offer mountain biking tours as well.
I hope that helps answer your question!