What advice do you have for a 3-year Reservist going onto active duty (with 10th Mtn Div)?

You can't really go wrong with any of the units up at Drum, they're all top-notch. It's a nice post, and Watertown isn't bad at all for a military town. Just keep doing your thing as far as PT and just do what you can to fit in once you're at your unit. Everyone loves the Medic though, so that shouldn't be a problem.

PT is number one. Be able to run. You will be judged on your ability to run (APFT).

Be in the right place right time with the right attitude and do everything your leadership tells you to do while being simultaneously good at PT and you'll be better than 80 percent of the Soldiers they already have.

On the Medical aspect of it look into TC 800 (table 8) and master the basics (M A R CH trauma assessment). Be able to do this with your eyes closed.

Every new Soldier in our unit gets a diagnostic APFT and Trauma lane Day 1. This reveals a lot.

Dont think that being in the reserves has set you behind the power curve. If your high speed youll be good.

I've done this myself. I will say it all depends on the unit, however active duty is completely different than the reserves and national guard. However given the fact that you are not that far removed from basic, I do not think it will be that much of a culture shock for you. Just have some expectation management and you'll be fine.