My life can be super busy during the week, so I cook meals (breakfast, lunch and dinner), divvy them into portions, and freeze them so I can grab and go.
Is there any way you can take portable dinners with you to eat on your way? Something like a hearty wrap or a drinkable soup in a thermos?
At one time I took a few college classes at night and had a similar schedule - Get my child to school, go to work, drive 40 minutes to school for 3 hours and drive back. At night, I could pack my snacks and meals for the following day - much easier because I already cooked and portioned them over the weekend - then I would heat up dinner and eat it in the car before driving to class.