"To get to China Wall you have to get over Kenosha Pass which tends to become impassable rather quickly."
You can also go down into the springs and back up Hwy 24 through Woodland Park, Divide, Florissant and get to China Wall from the South end. Personally I wouldn't do that trail with a bunch of snow on it. There's a couple hills that could get a little sporty for sure.
Rampart area would be good but they closed it April 1st for the spring run-off so the trails don't get all torn up, and I'm not sure what all trails are included in that, but I wouldn't be surprised if Phantom Creek is due to it being in that general area.
I know there's some trails I've seen other groups running up North around Ft. Collins area but I've not yet been on any trails up there except for one years ago as a passenger and I don't even have a clue what trail it was. Jim might know more about that area.
Bunce is so far the only one I've been on in snow (and not that much, just a couple weeks ago) that isn't too risky. I'm not sure what kind of rules and regs are out at Pawnee grasslands, but roads out there might be fun to run if they get a decent amount of snow. Personally I'm hoping we dont get squat. There's quite a few trails I've been itching to get on all winter and I know at least one of them is clear right now.
EDIT: The first time I went to China Wall last fall, we took rd 211 from Deckers down around Cheesman reservoir and ended up on Hwy 77/Tarryall rd just south of China Wall. Neat drive through all the fire devastation from years ago, I highly recommend it in the summer (there's a seasonal closing on one stretch of it) if you're ever heading down to that area. I'll have to dig around, I think I had a couple pics of the area.