crossbill,
I hope your son is 100% now. If I was in your shoes, I would make sure he is 100% healthy and able to perform. The second thing I would do would be to seek out third party baseball people to get a true, unbiased evaluation of his skills. I would then seek an appropriate national or regional showcase event that has schools that your son is interested in. I would then target those schools that have interest with a camp or an unofficial visit.
A PG (post-grad) year would probably be my last option due to cost and the relative importance of baseball to academics. As twotex suggests, it may be a good idea to give us a little more background on his baseball goals, academic goals and your financial goals. I think the board can be most helpful to you with that information. Good luck.