Within the training footprint it would be really hard to maintain outside college courses. Lots of time commitment during that process and a lot of new things to adjust to. Once you're free from that 6-8 week period college courses are an excellent way to be productive while sitting ready reserve or sitting in a hotel on a long overnight. With some seniority you could even bid to have long unproductive hotel stays for the express purpose of working on your degree. I haven't done it personally but many have finished degrees while flying for the airlines.