For those who have never biked or unicycled on a ski mountain:
All the ski mountains I’ve ridden on had mountain bike trails on them. Nobody wants to ride straight down the hill (okay, most people don’t). Northstar, for example, has a huge network of trails of all levels. Everything from easy (and relatively flat) fireroads to ultra-gnarly rock piles where I have to walk a lot.
Let me see if I can remember all the ones where I’ve “officially” ridden. Northstar-at-Tahoe, The Summit at the Snoqualmie Pass in WA, Fujiama Panorama Resort in Japan (Unicon XII), Snowbird in Utah (NAUCC last summer). The MUni race location from the Toronto NAUCC (I think that’s a ski place). Hmm. Is that all? I think I’m forgetting something.
Snowbird does apparently have a rule against unicycles. Our big group ride there was a first-time thing for them. Unfortunately a mountain bike race was apparently occupying the more interesting trails, so we had to ride down some pretty basic fire roads.
Riding straight down a ski run is generally too straight, and too steep to be much fun. Also, the ski runs are not “groomed” in any way during the off-season, so they’re grassy, rocky, bumpy, or whatever. I prefer a trail that traverses the runs.
It should be possible to do a Web search on “mountain bike parks” or similar, including NY, NJ, CT, MA. Though I’ll admit, some of the Tahoe resorts have no “summer” information easily accessible during the ski season, and vice-versa. Also you can ask bikers or at bike shops. I’m sure there are places out there.
If you go to a ski place to unicycle, I advise against asking in advance. If you ask, they may say no. Then it’s no for everyone. Better to just show up. Since a Coker is so obvious, I’d keep it out of sight until you go to the lift, if possible. If the people at the lift give you a hard time, just drop names like Northstar, Whistler, etc. and act like you’ve done it a hundred times before.
If it’s a “real” mountain, I think you’re going to want a brake… 
