Each site is different...call the site manager as early as possible and at least let him know that you are being proactive in your arrangements.
Some sites require appointments, some are first come, first served. They do not like being called at the last minute and being asked to make special accomodations.
Some parts of Goose Creek are very high security.....or were the last time I was down there...you may have to wait at the gate for an escort even if you have a military ID (Anniston Army Depot is such a case).
If this is the case you must be on time for your appointment.
You will also have to have current Drivers License, up to date tags, proof of insurance and anyone with you will have to have a photo ID. DO NOT CARRY ANY FIREARMS OR AMMUNITION WITH YOU. They have no sense of humor about this and they will either turn you around at the gate or arrest you. They can search your vehicle without your consent.
If you are arrested you will go in front of a Federal Magistrate.....if you get a ticket on post for anything it will be dealt with at the Federal level.
All that being said I used to go there in a Commerical Vehicle all the time and never had an issue.
Good luck with the recovery.