Thanks TPM. You raise a good point -- there is a showcase camp my son was planning on attending this summer, when I went and looked at the specific coaches who will be there, for the D1s it is mostly volunteer assistants. Very few PCs or RCs. May be OK for 2020s or 2021s if they're just looking to get on the school's radar, but may not be ideal for 2019s.
The college camp is different. The PC called my son and they spoke for ~30 minutes (and the PC also called his HS coach and spoke with him). Because of an untimely, early playoff exit, the game they were planning to come to watch him pitch didn't happen. They invited him for a visit, so he'll meet with the coaches and tour the place the day before, and then he's going to do the camp the next day and we'll see what happens. It's a little bit of a gamble, just in terms of cost and time, but he's not going in blind or as an unknown to the coaches.