Well. It's not the answer you want, but the Shinkansen and an expensive taxi ride or maybe a ridesharing with some local dudes might be a feasible, but not cheap answer.
Stay safe in those woods! I nearly perished, by getting lost.
I nearly fell into the river at Kagura on New Year's day! It was new snow that hadn't settled yet so every step I took the snow beneath me crumbled. I was on a ledge and trying very hard to climb up, luckily a few Chinese passed by and pulled me up. Then it was a long 2 hour hike back to the lifts.
