The honest answer
Cadets live in military barracks throughout their time in the Corps (a 2019 policy set a three-year minimum, with limited exceptions when barracks overflow — and in practice most cadets spend all four years in barracks). If you're joining the Corps, your packing question is the barracks list, not an apartment list.
The people who do rent in Charleston are Citadel Graduate College students, evening and degree-completion students, and veteran or active-duty day students. They arrange ordinary Charleston-market housing: conventional unfurnished apartments and houses in West Ashley, North Charleston, James Island, and peninsula neighborhoods like Hampton Park Terrace and Wagener Terrace near campus. Downtown student rentals in Charleston are dominated by College of Charleston, not The Citadel.
If you're renting in Charleston
Charleston rentals are almost always unfurnished — budget for the big anchors: mattress, bed frame, sofa, and a table.
Apartment checklist Apartment shop