Good luck getting a legitimate and educated answer from the CSFS.
The cats that run a commercial operation are required to have a permit, and permits are very limited. If you’re in an area where a commercial/permitted cat is running you will probably get challenged by the operator, especially if you’re hauling skiers, for poaching "the area they're paying for" with a permit. They will most-likely call the FS cops to have you checked-out as a non-permitted cat-skiing operator. Some are cool, some are not. There seems to be a real rift between some commercial cat operators and snowmobilers that like to use the same hills (that both have a right to use). I'm a sledder and there have been some nasty confrontations recently between commercial cats and 'innocent' snowmobilers hauling their friends up the same hill. You don’t want to 'innocently' get involved in that.
In CO, a private sno-cat that was built to transport people can be issued a snowmobile permit and used as such in areas that do not have specific width limitations for ORV’s. Any cat built as a groomer is not considered a snowmobile, private or not, and is not allowed on any public trail system (too big, way too wide).
Being smart with your routes is critical as you will be labeled "the instigator" if you have a collision with a snowmobiler (or anyone/anything else for that matter). Avoid any groomed trails or the groomers and most snowmobilers will hate you. Most x-country ski/snowshoe types will absolutely hate you, unless you manage to leave them with a real nice attitude and trail to follow when the snows really deep. Doesn’t hurt to stop and offer any assistance or tools if they look like they have a broken binding or look lost, cold, etc. Same goes for anyone in the backcountry no matter how they got there.
In the end, best option is to find your own areas to play in that don’t have snowmobilers, skiers, snowshoe-types, or any type of trail that someone is paying to have groomed or plowed. Do that and you won’t have to answer to anyone and won’t add to the hornets-nest involving motorized vehicles vs. leaf-lickers. Ask too many questions from the wrong gov’t official and the next thing you know we have a whole new set of rules and regulations that will eventually ban private sno-cat use in public areas.
The only thing the CSFS has that you want would be the trail maps that show motorized routes for winter and summer.
Be smart, be safe!
