What should I expect from being detailed to the USMA? What does it mean if my tasking is “CBT 1 CO medic”?

By the looks of it, you will be providing medical coverage for a cadet basic training company. Probably sick call duties and range coverage.

CPL (Join to see) I would like to add to the answers that you have gotten this one important thing.
USMA Cadets will judge Army enlisted Soldiers by what they see in you and those detailed for the summer to the Academy. Present the best, most professional appearance and performance that you are capable of. CBT is Cadet Basic Training...Basic Training for brand new just left civilian life Cadets.
You will be the first example of a Professional Enlisted Soldier that they see. Make a good impression.

CPL (Join to see) I only spent a couple of weeks there TDY, in 1993, to assist the USMA MP Co. for security during their graduation when POTUS Clinton was the speaker. The permanent party MPs had regular barracks with rooms with a couple of occupants and had their own or shared bathroom with an adjoining room. The barracks that the non-permanent party MPs stayed in were old school open bay barracks. Also, pretty much everything, at the time might be the same now, was tailored to the cadets (gym hours, PX, Commissary, etc). It was irritating because I couldn't get to the gym when I wanted to, but it makes sense since USMA is there to teach cadets how to lead. If you are being permanently assigned and not TDY, I'm pretty sure you're going to live in modern type barracks. There are probably more amenities for those that are not cadets.