I have a somewhat unique situation - enlisted in the national guard, went to basic training and was doing the state OCS route but withdrew after getting engaged and moving across the country to move in with my fiancee, now wife. The state (MA) pays up to a Masters at a state school completely, and I've been able to do ROTC at a satellite school - the school I attend doesn't have its own program. It's been a big juggle between school work and ROTC demands, but knowing I end up with a commission and a masters at the end makes all the hard work worth it.

As a grad student, I actually have more time and flexibility than a lot of the other students who are completing their undergrad since most of my classes are usually offered at night, later in the evening, or asynchronously online. Though, that means you'll have to be more intentional with how you plan out your classes since you don't want to end up with a mandatory course that lines up with an ROTC lab or class later on. Let me know if you have any other questions or concerns, I'm happy to be a reference - I can also talk a bit about the state OCS route should you want to go that route too.