I think people have a misconception about general "access" to the head coaches of the BIG programs -- quite unlike the JUCO's or DI-DII schools. Access can be quite limited.
My son's prospective coach (Big 12 school) told him that he may never see him pitch until the pitching coach decides if he likes him. I know it's different for walk-on players, but I get the impression that players at that level do not have a close personal relationship with the head guy.
To a large extent, the assistants run the programs -- the camps, the recruiting, the fall activity, the workouts, etc. That's not an indictment, just a fact. And that's fine...hopefully, a recruit has a healthy respect for his position coach and/or the assistant coaches before making a decision on a school.
All this stuff really adds to the intrigue, eh?