I'll chime in- we go to Hatfield McCoy probably three or four times a year.
We typically stay at Devil's Backbone ATV resort. It used to be the best kept secret on the trails, but now not so much. The cabins are pretty pricey at this point but they do have all levels of camping available and a general store / bar and restaurant on site.
The best part for us is that it sits smack dab in the middle of the Northern Trail systems, so you can ride about 50 miles one way to a town and eat lunch and then come back, and then the next day ride 50 miles to a different town/eat lunch/come back all without trailering.
As far as the difficulty of the trails- probably 60 to 70% of what you're driving is also gas company land and could be done with a four-wheel drive pickup truck (operated by a redneck with big balls). We don't ride a lot of black trails: we found that a lot of them aren't just steep but also have giant rocks and we don't have much of an interest in tearing up the machines/ testing the local healthcare system. It certainly interesting enough for us, but take that with a grain of salt.
So far is the lower loop goes, Ashland resort seems like the place to stay. Same kind of deal-it's a full day ride to the top to eat lunch and come back, and then a full day ride to the bottom of that trail system. Makes for two complete days of riding if you really like to go out and cover some miles without riding a lot of roads or trailering to a trailhead.
50 bucks for the year (per passenger) is hard to beat as well.
As far as time of year goes, I would recommend either spring or fall. It gets so busy and dusty midsummer that it's almost no fun.
If you're coming from the north they just opened two new Trail systems- catabawinga and the name of the other one escapes me. They're nice to stop, unload take a little ride to break up the trip and move on but no more than 3 to 4 hours of riding total there tbh. Not connected to any other systems.