Training on the Road
Improvisational training deals with finding ways to exercise when you are away from home. Calisthenics works well here. Calisthenics are exercises that use your bodyweight as resistance as opposed to having free weights or exercise machines. Push ups, Pull ups, and Body Weight Squats are basically a Push/Pull/Legs split that goes with you everywhere. Since it is bodyweight stuff, make sure that you do a lot of reps. It's not perfect, but it can keep you in shape during those long, hot summer road trips.
As for food on the road, try to get some protein with your meals. This could be as simple as getting some milk to drink from a gas station as opposed to a soda. Certainly meals from gas stations are never the most nutritious, but with some effort you can make them as good as they can be.
Also, if you have a job that keeps you on the road for long periods of time, you may want to ask and find out which hotels have gyms ahead of time. It seems to me that more and more hotels are offering at least a basic exercise area, so it could be easier to find a hotel with a gym than it was in the past. This will allow you to workout however you want from anywhere in the world!