I'm concerned about horses in general because a riding stable in Kerrville was sued recently when a child fell off a horse. I don't know the extent of the injuries, but the stable had to close it's doors.
There's a lot of things I need legal advice on.
DG I just found a weekend job for you and your legal team! ;-)
Unfortunately there is always that one arse that comes along and spoils it for everyone. Kids with downs sydrome really like horses. Of course they can never ride on their own, but just getting in the saddle and being led around the ring is an accomplishment to them. Insurance will probably be your biggest cost, which you can reduce by having proper waivers drawn up for parents to sign.
Regardless of what activities you have available, they should all end with an award, ribbon or something of aclomplishment. I'll see if I can find if some of these camps around here have web sites.
You can go to the free republic saddle club thread for more advice about planning for a stable. I used to work for a couple for quite a few years as a manager and instructor.