Another good facility is in Charlotte, Tampa Rays. They have great food!
This was son's fav stadium while playing in the FSL.
Go to a ball game, then go fishing, then go to the beach, do stuff you and he wouldn't ordinarily do. To get to one point to another on the west side is easy but don't spend all of your time in the car.
smalltownmom makes a good point that towards the end of spring training is the best when the starters are more in the game than just a few innings as they are in the beginning, but do not go without tickets.
Justbaseball's advice to hit the backfields is awesome, this is where you will find the players of the future and they are eager to sign anything you ask them to (just not while in a game). However, I am not sure how much meaning it has for a 10 year old boy.
Have fun!!!!!