JUCO recruiting constraints

D1 and D3 allow no tryouts. D2 allows a tryout of a high school senior, but not during baseball season.
JCs are typically relaxed regarding tryouts and NJCAA has no rule against it, but there are several governing bodies for JCs in the US. I haven't checked rules other than NJCAA.

Colleges are allowed to hold or participate in camps, which are ostensibly instructional. However, camps can provide the same function as a tryout.

My son has attended 3 private workouts for/at junior colleges. I would assume this is legal because it never seemed to be a big deal or hidden. At one he worked out with the team during practice.

I think the recruiting restraints for CA JCs deal primarily with how they are allowed to deal with players at another JC or out of their area of influence. I think that primarily applies to CA JCs.

CA JCs

NJCAA also has very strict rules regarding communications between coaches and players of other NJCAA programs. I am quite sure that coaches cannot approach an affiliated programs players for recruiting purposes.