If buyer doesn't buy she is going to say Buh Bye, I'll send a check later and friend is going to be broke college student with rig and horse 400 miles from home. If she does buy, is friend going to tack on the $300+ or so it's going to cost in gas to get there plus motel and any flats or other repairs that crop up? How about for hauling the empty trailer back?
No, that's not fair. Fair is person requesting the horse be hauled down there pays in advance for horse to be hauled down there-and returned if they don't want it.