One way you can keep your fitness level up while on the go is to work your stomach out while driving. Simply tensing your stomach muscles for five count then relaxing, multiple times over the course of your commute will not only make the time pass quicker, but will help to tone that stomach in otherwise wasted time.
To get a better looking back, you should focus on all four of its muscle groups. Exercises like forward back bends and power shrugs will improve the look of your upper back, while leg lifts and back crunches are great for the lower half. Working out your whole back assures that you'll be able to see the results of all your hard work.