"If I had to do it over again, and I wish I could, my 2012 would not have done a PG at IMG as academically, he didn't need it. He would've done a "gap year" that we created with the following: taken some junior college classes (though not enough to impact collegiate eligibility), SAT/ACT test prep and test again to maximize the number of schools he could be a candidate and maximize merit scholarship opportunities, work to make spending money and savings, volunteer, continue to develop his baseball skills via individual training, work on speed, strength, and agility, etc.. For game action, in many areas of the country there are fall and winter leagues/programs. Our local college runs a league for high school kids here. In the Spring, there are places to play in a few areas. Adult leagues, college camps, etc. all can provide some game action. My son ultimately played in a SoCal league the Spring of what would've been his PG year after we left IMG."
This idea is something I have thought about for a long time. I think your plan is extremely well-thought out.