i would think wv is the most dirtbike friedly state i've ever ridden. probably the most dirtbike friendly on the east coast aside from maine maybe (i don't know the law there...)
here's the law:
use is banned from paved roads with a CENTER LINE or more than 2 lanes, except to cross and EXCEPT for getting from one trail or field to another when traveling up to 10 miles no faster than 25 mph.
All must be titled.
All riders under 18 must complete a rider safety awareness course.
All riders under 18 shall wear helmets at all times.
No passengers are permitted except if the ATV is designed for a passenger or if the passenger is at least age 18 and the operator is at least 18 and has a driver's license.
shall not be operated from sunset to sunrise without a lighted taillight and headlight.
so, if the road has a center line, you can travel up to 10 miles, no faster than 25mph. - but i've read elsewhere that this is not the law...
if the road has no center line (i would guess 50% + of the roads are rural here, and none have paint on them....) there is no real law, aside from standard rules of the road.
i regularly see atv's and utv's on the roads here...
as for the 10 miles, if you can't find a trail or unpainted road in wv within 10 miles you're doing something wrong.
i regularly zip down a 2 lane 55mph painted road to get to other trails. i believe the police are so used to this, that they rarely hassle anyone.
needless to say, afaik we have the highest fatality rate among atv/dirt bike in the us...