I understand it is late for this, but after actually having attended a couple of minor league ST games, here is some insite for next year.
You can just walk in and watch games. As far as the schedule, I am not sure where you can find it. There is one, but the minor league camps will only play teams from about three different organizations. The Phillies, Yankees and Rays would be the most likely competition. If you go, you most likely will be the only one there and will have to share the stands with the players. There are typically two games going on at once. On some days, Lansing / Dunedin will be playing on others it will be NH and LV. It isn't really structured and you will have to keep score if you want to know what is going on. Some games don't even have umpires as I watched the catchers call the balls and strikes once. The players are playing for jobs and position in the minor league system, but the camp atmosphere itself is completely different from the MLB boys.