Cuyuna (in North Central Minnesota) IS fantastic! I took the boy for 3 days to celebrate his 10th birthday. It's unbelievable what they've done --and are doing-- in that area!
For those who don't know the story, here's some background:
I think they're up to just over 30 miles of trails and are constantly adding more. Everything about it was perfect. The town (Crosby) is your quintessential small town and has completely embraced the bikers. The downtown has lots of restaurants, antique stores, and support for the bikers. Although we brought our own bikes, I was really impressed by the available bikes for rent at the Red Raven. You can get a day on a full suspension Santa Cruz for $50, for instance.
We stayed here:
https://www.truenorthbasecamp.com/
One night we stayed in a cabin and the other was at a beautiful campsite. Both were on property and you could wake up in the morning and ride right into the trails. The trails themselves are rocky (as you may expect at an old mine) but really nicely managed and marked. I had a map in my pocket but never needed it thanks to the kiosks, trail signs, and unbelievably friendly people. We stuck mostly to greens and blues but did tackle one black, which proved to be too steep a climb for my son but none of the 3 or 4 riders who passed us batted an eye when they had to maneuver past him- every one of them offered encouragement on the way by. Eventually he made it up and shredded the decent.
I'm still relatively new to mountain biking so I can't compare it to much, but as a destination this was about as much fun as I've had in a really long time.