Congrats on the assignment. There were many times while I was in the Marine Corps where bowling simply wasn't a possibility. If you want to maintain your bowling shape and mind, you are better off trying to fit in the best practice sessions you can when you can. Subbing will be difficult depending on when you get released. Can't remember if it is before or after dinner.
Another option, put bowling on the back burner. Take this opportunity to devote yourself completely to what will be an extremely challenging time in your career. Being a DI will be physically and mentally draining, as well as time consuming, and I am betting you will have very few times where you will want to go practice.
During my time in, I don't remember any DIs that bowled competitively.