There is no problem because you can go by ropeway.

I've driven there and the road does have quite a few bends. Nothing too sharp. But based on my experience with buses in Japan, they are driven rather slow, and the ride is quite comfortable - motion sickness should be the least of your concern. Else you can buy motion sickness medicine called "Travelmin" (available for juniors as well) which is available at some convenience store / drug stores.

Takayama at least 2 days for Morning market, Takayama old town district and its Temple and shrines as well as Onsens. For Shinhotaka Ropeway you need half a day, unless you wish to go for onsens, otherwise footpath will do. As for cloudiness, I’m not sure as We’re there in October. The autumn leaves are beautiful during November. Don’t missed it. Thank you Lim

Is it at its peak already? If yes, that mean there wont be any autumn foliage around end of November? Thank you for your answer.

May snow most unlikely, go dec or Jan see snow

It would vary though. I was there at early January, so I can only stay outside the station up to 45 minutes. After that, I sat at the restaurant, ate lunch and starred at the outside scenery for about 1.5-2 hours. If you come on other season, maybe you can take a longer walk and hike around the station. I recommend at least 3 hours there, and you have to PLAN YOUR TRANSPORT WELL, right from where you are staying, back to that place.

Foliage season(Saturdays, Sundays and national holidays in Oct) The from Shin-Hotaka Onsen (the up) first train 8:00 The from Shin-Hotaka Onsen (the up) last bus of the day 16:00 The shirakabadaira (the up) first train 8:15 The shirakabadaira (the up) last bus of the day 16:15 The Nishihotakaguchi (descent) first train 8:15 The Nishihotakaguchi (descent) last bus of the day 16:45