Rode at quarry park mid day today, conditions were perfect, no other tracks were to be found but after i'd been there for a bit a group of 5 other riders, two on fat bikes, showed up but I didn't know any of them.
I just got back from a couple of laps with Jin at Quarry Ridge, really nice out there too and surprisingly there were no other bike tracks that we saw. Going up requires hiking, but the down hills are a blast and the sandy bowl area is completely untracked. We'll be out there later in the day on sunday most likely, it's too good to pass up. BTW, hitting the big wooden wall ride would be quite the feat in the snow, it is rather slippery.