At least skiing is allowed in most 'Forever Wild' lands, to my knowledge. As a mountain biker in Catskill park, I can rip awesome trails on private lands at Roundtop and at 'Elm Ridge Wild Forest' but not continue into the 'Windham-Blackhead Range Wilderness'. In terms of Dacks snowmobiling, imo the abundant trails make sense, given the snowpack and historic roadbeds. Not sure, but snowmachine folks don't need steeps to get their tingles? Here are some thoughts about backcountry skiing in these areas...
I figure the Dacks would be offer good XC skiing, but seems limited for shorter laps with heavy AT gear. The terrain also doesn't seem as conducive to my lazy dream of a quick hike in to a continuous 500'+ vert of solid 20-40 degree downhill, without major terrain traps. My knowledge-base for backcountry 'round there is nil, I live too far to scout potential areas. I bought a 'Slides Guide' which contains only aerial photos of many Dacks slides, many of which look like they would be insanely fun, challenging, potentially very dangerous. I imagine most/all require extensive approaches, potential mandatory mountaineering/rapel/ice climbing moves. In a normal time perhaps an excuse to hire a guide and gain some skills.
I've been hiking some historic road/trail routes in the Catskills, Taconics, and Gunks that could be good with 1-2 feet of snow. Obviously snowpack is a limiting factor here, but hiking round some relic ski areas recently has got the stoke building! If anyone wants to connect and potentially do some AT skiing this winter, feel free to send a message