ROTC cadets and midshipmen have their own college academic year and summer training programs. During the summer, I know USNA and NROTC mids are together on some training cruises and evolutions. I would assume similar happens with other services.
As far as opportunities to work with SA cadets on SA campus, I am not aware of any at USNA, don’t know about others. I am sure a current mid or recent grad can speak to any NROTC presence at USNA. Only a handful get to do the exchange semester at another SA, in any event.