Thanks will check this stuff out!

 

The US Forest Service has maps in .pdf format at http://www.fs.fed.us/r2/blackh...management_maps.shtml

you can also find lots of information about the riding in the Black Hills by googling "ATV riding Black Hills" At this time there is no ATV or UTV trail system in the Black Hills. Most riding is on what are called FDRs (Forest Development Roads) which range from primative to impassible. There's about 5,000 miles of FDRs but not all are open to motorized travel. The Black Hills National Forest has about 1.4 million acres of public land of which 800,000 acres are still open for unlimited travel (this, however will soon change).
Snowmobile trails on public lands are also open to ATVs after the snowmobile season (Dec 15- Mar 15). Where to ride? Generally most of the riding opportunities are in the northern and western Black Hills. The old gold mining districts between Deadwood and Hill City are popular, as are the trails around Nemo and Hill City. Custer and Deerfield also offer lots of opportunities.
As for the terrain, it ranges from sedate to extremely challenging. It helps to talk to a local about where you would like to ride as some areas may be too difficult for inexperienced or younger riders.

 

You didn't say what facilities you need but if you are looking for a fairly basic campsite away from crowds you might want to look into the campgrounds operated by the US Forest Service in the Black Hills. Theres a list at http://www.forestcamping.com/dow/rockymtn/blkhcmp.htm

A good one for ATV riding is Ditch Creek Campground near Deerfield Lake in the Western Black Hills. There are trails that leave right from the campground.

This campground is somewhat remote which is either good or bad depending on your taste.