For the time of your life on an ATV, try the trails at Elbe ATV location. There are nearly 5000 acres so there is a lot of room to spread around. There are no overt restrictions so mostly anything goes, but always keeping in mind, once on an ATV you're a driving example of the best qualities of the sport. And what a sport it is. It takes all your concentration and muscle to tear around on an ATV even under perfect landscape and weather conditions.
And, the conditions at Elbe change with the seasons. If you like dry, claylike runs participate in dryer months. On the other hand, if you love mud, no, if you LOVE MUD, make sure to stop by this place in the wet seasons, usually spring. There is more than enough mud to go around. If you're planning on entering any ATV races where there will be mud runs, this is where you want to get down your mud skills. No one is watching you, go for it.
Make all your "Duh!" mistakes here. Learn to throw your ATV all over the track without throwing the ATV over the track. Be very careful in mud situations, not all lumps of wet clay are dirt; some lumps of wet clay turn out to be lumps of little people. Kids are drawn to mud like flies to well, let us say sugar. Just be sure your kiddos always ride wearing all their safety gear. A helmet should always been worn and eye protection above all, as muddy conditions can kick up a lot of debris and ruin an otherwise extremely fun ATVing time!