I wish I knew as well. Have had the icon in my quest queue to purchase a tamarind tree for 3 months, but have no way to get to Tombstone in order to do it. I am as befuddled as you as to how we obtain the stagecoach. Maybe we have to be at a certain level or have to have completed a specific task somewhere along the way that we missed. OR maybe it is another lovEly bug in the system. Whatever it is, I would like to be able to get to Tombstone on that dang stagecoach!