There is a BOQ on the Air Force Base, but I'm not sure how they would treat you trying to get a reservation. Worth a shot however. Info Below.....
Inns of Charleston Phone -
Commercial: (843) 963-3806
DSN: 673-3806
When I left Charleston back in 2004, there wasn't lodging available on the Weapons Station for JO's assigned to NNPTC.
I recommend you contact NNPTC
https://www.netc.navy.mil/nnptc/contact-us.htmAsk to speak to the ADOD (Administrative Director, Officer Department), and see what he can tell you.