You can come to the Beautiful Black Hills of South Dakota. Basically, the hills are 100 miles long and 50/60 miles wide. The entire area is covered in trails. Check out
http://www.dakotaadventureloop.com/ or
https://www.dakota600.com/Although both of these links are not exactly what you were looking for, it will give you some insight to our area.
Also I belong to a local (actually about 5 states) dual sport group.
http://dakotadualsportriders.com/ We have a couple of rallies each year. Often we will have people that join our rally in conjunction with their other riding visit.
One more thing, check out Adventure Rider
http://advrider.com/index.php and search above names. That will give you real reviews from people around the country. There's at least one thread on ADVrider that is strictly about single track in the Black Hills.
Questions, just send me a pm. LD