keep this in mind - if you go weekdays, there is almost no one on the trails. i can ride all day weekdays and see less than 10 riders. this is the best..
if you want single track, by far the best (and least ridden) is matewan (buffalo mountain). if you want fast single track, rockhouse is also good, there are some extremely difficult trails at both rockhouse and buffalo mountain. i've been stuck good at both of these on my trials bike...
the quads are out in full force on weekends at rockhouse and little coal river...
little coal river is definitely skippable, it's a bit more sandy, and mostly beginner type quad trails. it's the closest one to me, but i skip it. it's very family oriented..
rockhouse is definitely rocky.. there are lots of sections that are solid flat rock, and lotsa babyhead on hillclimbs. rockhouse is more 'groomed' to some extent.
rockhouse is also the one that is designed best for out of state visitors..
you could spend a FULL day at each easily (you can easily spend 2 or 3 days at rockhouse...or buffalo mountain if you decide to do the really challenging trails.....DO NOT start a black trail late in the day. i've heard of people spending 4 + hours on black trails rockhouse that are only 2 or 3 miles long... ) for example, i can go down trail 199 at rockhouse in about 20 minutes. it takes a long time going up it...you could spend between an hour and 3 doing it... here's a vid going the uphill way - it's only a snippet of it..
http://www.youtube.com/watch?v=xUY1DnU_w3o
i would start south and work north. buffalo mountain to rockhouse to bear wallow...
bear wallow has about half of it shut down (or did last year) due to blasting in the area.
their trail marking system is accurate. sometimes you enter a black trail and think, this is easy, then you get to some crazy section.....and you understand why it's marked like that....
i would not recommend going in the heat of summer. the trails get really dusty.
matewan is very challenging in the winter. last time i went there was 6 inches of snow on the ground.
oh, if you have any 'fear of heights' issues, hatfield mccoy may not be for you. there are LOTS of sheer drop offs, and treacherous stuff. definitely bring spare tube or run tubliss/mousse i've pinch flatted more than once there. not had a problem since switching to tubliss.
oh, and none of the videos really show the magnitude of these trail systems, nor the elevation changes. there are some serious hills.. and each system is big enough to get lost in. i carry maps of the trails in a plastic sleeve sheet protector zip tied to my handle bars, so i can navigate quickly. i also carry several copies of the maps in ziplock bags hidden away. without a map you can get pretty lost, even though trails are very well marked.
90% of the time i ride alone there. probably not the smartest, but that's how it is. there is spotty cell service on the trails.