I haven't ridden down there in like 13 years but Wycolo Lodge used to have fuel. Albany Lodge, north up the trail a ways, has fuel.
Not familiar with the off trail riding down there. I know if you get up towards Rob Roy Reservoir there is off trail riding.
There are unlimited off trail riding and challenges north of U trail, off N trail, off eastern V trail, etc, but those are quite a ride north from Fox Park.
Q trail is interesting, but long. Most people head north up T trail to get up the the good stuff, and, the scenery is great if the weather is clear.
If you decide to venture up that far, take at least 2.5 gal extra fuel per sled and you could always stop in Albany on the way back to put in some fuel (in addition to the extra fuel you carry).
If it is windy and snowy, best to stay south of U, or at least don't go much north of like where T meets W because it turns into a whiteout really easy up there, wide open.
I don't think it would be worth getting a CO sticker unless you want to trailer down to Rabbit Ears by Steamboat Springs.