Trying to get out of the ruts and into the fresh snow becomes a game. lol
Sugar Pine is pretty but I tend to avoid it and especially Sly Park because it's a favorite spot for large groups of Russians to hang out and party. People have been trapped on the lake because the partiers hang out at the boat launch area and threaten boaters truying to leave. I had 2 guys in a Mercedes use the boat launch as a drag strip and they almost hit my family as we crossed the road on our mountain bikes. That's my experience though others may have had better experiences out there.
I prefer to camp near Bowman Lake, Jackson Meadows, Webber Lake, or even Ice House way over by Hwy50. I'd also suggest heading up to the Downieville/Graegle area. Tons of lakes and lots of dispursed camping and some great off-road trails.