Going to Ft. Eustis for 15T training as a Sgt. Will I have to live in the students barracks and be treated like a schoolhouse boot?

You should end up in Hotel Company, which is cake. As long as you're in the right place, at the right time, in the right uniform you won't have any issues. When you're not at PT or in class, your time is yours. The instructors at the school house will leave you alone for the most part. The IET PSGs will leave you alone unless you cross them in some manner.

Yes, I’m currently here for ALC which is a NCOPD school and I currently am staying in the barracks that you will be staying in. You will have to pull CQ and play the tradoc rules you will have more freedom as you can go out on the weekends and such but for the most part you are there to train and learn a job.

They should have a barracks for prior service and people who re-classed.
You still have to abide by certain rules and regulations, but at least you have liberty after class.