Still available, kids are ok to ride.
The Lodge has a stable with horses that provides guided rides, usually an hour each, around the farm property. If you want longer rides, that can be arranged as well... You sign up for the rides at the Lodge office.
I know that one of the guys who attends the rally every year has arranged for his wife to "lease" a horse for the entire weekend so that she can ride whenever, wherever, she wants (easier for them then bringing her horse to the rally in addition to the MV).
Info on the horses at the Lodge Stables is located at:
http://www.gravesmountain.com/activities/recreation/
Also: The field next to the one that we use for the rally will have folks camping in it that bring their own horses...