For a personal tour of the college, probably not as an 'organized activities' for the most past. Casually yes, sure. "Hey I can show you around and chat" is different than "Coach would love for me to show you around and chat" or even that Coach has instructed the student to offer this up to a prospect.
I know that all feels like a fine line - it is. The NCAA rules are complex, often contradictory, regularly stupid and somewhat petty when it comes to this and you are better off NOT doing some things without the college's NCAA Compliance officer clearing it. Blame past behavior of POWER 5 conferences/coaches in most sports including softball and then football/basketball in general for the most part
Ad hoc activities such as Social media, emails, phone calls are all good between students.