I havent been there lately, traditionally its plowed up to the fish hatchery. As commented by many, the gate is generally left open to enable them to plow it. If it is closed, it is rarely if ever locked and worse case is that you would need to go knock on the door of the houses near the gate.
There are no guarantees that the road is plowed to the Bunnel Notch trail head from the actual hatchery buildings, but it normally is. (it was last winter)
i've never not found it plowed at least to the parking for unknown pond trailhead (also the parking for bunnell notch/york pond trail if small area isn't plowed out in front of gate, though it was when i was there last winter). the only issue with that road is that it can be awfully icy and slippery even after it's been plowed. i recall a few slips and slides over the years.
beautiful area to hike in the winter.
Good idea by bryan...road is in good shape some icy spots..also watch for snowmachines just after the WMNF boundary marker and the bridge over the Upper Ammo...
information updated Friday 2/12 I went for a ride this AM...from the bridge, road is "white ice" with minimal sanding, so just be careful on the corners..trailheads are 7 miles from Rt. 110 and plowed..enjoy, Keith
we drove in to York Pond Trail head today...2/14...on a trip report you would call it "blue ice" in several spots once past the main hatchery( dirt road part).. had a little snow on it and a little grip and there was no problem getting to the end at 25mph or so..all parking lots plowed out
To mirror Silverfox's comments, I was up there Saturday (2/13). Road is plowed all the way to the York Pond Trail head. The gate is apparently not used in winter as it was clearly plowed in and buried under the snow. I had 4WD and used it on the icy stretches. It's a mix of bare road and thick ice. I'd be very careful on some of the hills and corners - could definitely start to slide on spots...