Kids would enjoy all of the singletrack, as the hills aren't too steep, and all obstacles are fairly easy to navigate.
Watch for signs of where work is currently underway and do not hike that section.
The singletrack starts from the right side of the lodge as you look at it. There is a sign at the beginning of the trail, which makes access pretty easy. Enjoy this trail which smooth and rolling until the end. From there, hikers can either return on this trail or take one of the ski trails back to the lodge.
The current length is 5 miles (08/2016), but the full extent of the trail will be closer to 13 miles when construction is completed. Have no fear, the trail is marked where it is currently under construction, so you're not likely to stumble off the well-worn track.