I assume you have the academics part of the equation down, but I'd have him taking the SAT/ACT as soon as possible once he's ready. Also, since you're in Maryland, there are ample opportunities for quick trips to visit lots of HA's (which seem to concentrate in the East). That will help determine the type of school he thinks he likes.
Rather than showcase before he has something which stands out, I'd pay instead for top of the pack personal PC and strength trainer skilled in pitchers.
My son sat 80 - 2ish sophomore year and attended Headfirst and Stanford camps as a rising junior - but he was also shorter and lighter than your son at that age. That - combined with clear top academics - was good enough for coaches to follow him and when he returned to those camps as a rising senior the same coaches came to see him (velo now sitting 85 -7). My son never played any real travel ball (just several seasons of Scout ball), just locked onto a great PC who developed his pitching skills and worked hard.
As you probably know, the velo thresholds have risen substantially since you played. Ivy's profess to seek 90, but I think 87 with control and a "magic pitch" gets big attention. D3 HAs are a bit less.
If you haven't done so, take him to a college game. If you're in the DC area, the collegiate summer league also provides an opportunity.
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