For Army ROTC, most instruction is campus based. Unless something has changed, there is no formal training after MS I and MS II (freshman and sophomore) years. Most MS IIs will compete for Airborne and Air Assault slots. Cadets who joined late can also compete for scholarships at Basic Camp. Get a good job/internship for MS I summer. The first three years of AROTC training prepares cadets for Advance Camp after MS III year. Advanced Camp is a 35 day training event to prepare cadets for commissioning.
U.S. Army Cadet Command's public web site.
www.cadetcommand.army.mil