[RWebb]

1st - call it Jackson like the locals, not Jackson Hole - it is a "Hole" - a sort of circular valley so-called by the early trappers ("mountain men")

the back side of the Tetons is where the fun is for me and for various dirt-bag climbers, skiers, etc.

there is also an awesome telmark style traverse I can almost recall nowadays - is that something for you?

an easy XC ski is to follow a road in from the entrances - the NPS can tell you all about those

be very careful of the hot springs - people do crash thru and die periodically

not sure re renting winter clothing but when doing XC skiing you will generate lots of body heat, so be sure to dress in layers

you can also get rides in a snowcoach and they may still allow snowmobiles in the Park (I almost barfed on one of my graduate students when he told me did that {but he was from Iowa})

post more specifics and recognize you will need 6 weeks to acclimate well to the altitude and cold, so...

Once upon a time the Appalachians were the highest mountains on this continent and much higher than the Rockies are now.