Return visit versus local follow up?

S visited JHU in February of his junior year. He attended a pre-registered info session and tour, and checked in with the admissions office upon arrival.
Since it was junior year, it was too early to interview.
JHU remains on his list of colleges of potential interest. He is now wondering if it would pay to drive south again just to interview, to demonstrate his continued interest. I am wondering if his attending a local info session with a rep in our area and/or having an alumni interview would suffice, since he already visited.
Anyone’s experience suggest whether an on-campus interview makes a big difference? (Note: in middle 50% of accepted applicants statistically.)

I would think a local interview would suffice unless you are particularly close. However, if he is considering ED, he might want to spend one more day there to confirm it’s his first choice. In that case, I would schedule the interview as part of that trip.