Dear Kristin:
My thoughts: on your long commute, see to it that your posture is right, so you don’t hurt yourself sitting the wrong way for so long. Also, on your commute, a simple exercise as rotating your wrists once in a while or gently, rotating your neck when in a stop sign, and just moving different muscles and joints will be helpful, on the commute (as is not disruptive to driving, of course). It will not give you aerobic exercise, but every movement is helpful and will keep you in touch with your body.
Then if you can incorporate a few selected exercise moves in the morning, five minutes, that will be helpful. Or in the middle of the day. Then aerobic, twice a week, half an hour each time, such as a brisk walk, can do wonders.
anita