I was a 68W and lost my NREMT when I discharged. I have to go back to San Antonio to retake my NREMT. What should I expect?

As an NCO you are entitled to all the privileges of an NCO. You will have less restrictions then E1-E4. If you were to go through BCT, you would have your own room, have access to your phone and or computer after duty hours as well as the ability to travel freely around the post outside of the training schedule. I would imagine that this holds true for Fort Sam

Being Prior service you will not be housed with the individuals straight out of basic. You can expect to have a room to yourself due to the COVID guidelines.
Although you are not housed with the rest of the class, you are expected to be at all PT sessions, study halls, or other company-wide events. I hope this helped. I am not sure when you went through the first go-round, but Whiskey land has made some major improvements.

I did a year at Ft Sam last year for prior service reclass (68a) Can't comment on what the 68w training will be like because I dunno other than they do more physical pt (ruck marches, stretcher runs) and they wear full kit during the school day. Living at the prior service barracks isn't so bad, no alcohol in the barracks but the gazebo on Friday and Saturday nights will be hopping. Dont play with the boots, easiest way to get kicked out of your course.