Apr 29 Fuji-san, Japan

Disclamer: I have limited experiance in mountaneering. On the other side I am russian so I like cold weather and have "whatever" atitude. As result: do not follow my example.

I took bus from Shinjuku to 5th stage. You can get snow ~100m from the 5th stage.
I had only 5 hours till the last bus back to Tokyo so I had time to hike up to the 2900m altitude on my GPS only. The snow is icy so clam-ons would be better, then snow shoes. There is soft snow in concaved areas. I would stay away from it because it sits on top of the ice and very easy shifts down the slope. Ice pick would be really helpful to stop you from sliding down all the way to Tokyo.

Also check wind forecast. I would not take snowboard in anything above 20knots. Sometimes it gets 50knots gales and your snowboard as a sail wil easy overpower you.

Aparently I have much more experiance on snowboard then in hiking so ride down was very easy and pleasant. I did not have a map of terain so I relied on my GPS to get back to 5th stage. In any case, the mountain is crossed by road at the 5th stage mark so it would be hard to miss it.

Good luck.