I am no longer actively involved with the project but things seem to be doing quite well without me.
Make a stop-over at my ex dacha part of your Moscow to St. Petersburg trip. Unlimited area to ride. You can go into the fields unaccompanied if, of course, you have the skill. The total cost, including accommodation, food, and assistance with horses, is $50/person/day! See Horse riding and the dacha experience or the Russian original of the horse riding site.