It really depends on the weather. When it gets bad enough, the county official will "close" the park, but that is only in the winter months. Rocky Knob tops out at around 4000' so it gets pretty torn up from the freeze/thaw action all winter. Adding to that, 1/2 the park is north facing so it doesn't dry out as fast. Play it by ear in February, because you never know, but I wouldn't plan on it.
You can hike there. The trails have signs for what direction to hike and what direction to ride, the jump trail is off limits for hikers. There are some really smart people who like to run with headphones in, it's only a matter of time until there is an accident.
Douchebags in Bent Creek run by you with eyes averted like they're listening to Charles Manson, motivational speaker. Not sure what it is about exercisers and riders with headphones on in the forest, but it creeps me the heck out!
Purpose built for bikes, but hiking is allowed in certain directions and on certain trails. Not many people hike there though. Butch, its been there for 2 years now, and is one of the coolest things that NC has going right now for bikes, and you still don't know the 411 on it, whats up with that? Get out there and ride. No excuses.
For those who don't know, Rocky Knob is closed right now due to freeze/thaw conditions. We're in the middle of our second day of rain and have cold weather coming back soon, so I would not expect the Knob to be open for the Winter.
All trails at the Knob are in great shape. They tidied up any erosion damage from the winter and improved a lot of spots that had water drainage issues. The parking lot is busy now with improvements so parking is limited.