Hotel room workouts. Like p90x or tapout. I dont bring the dvds, just do those kinds of workouts. Can always fit bands in my bag. Joggin is always an option. As for food, lots of convience stores sell fruit. Grocery stores i find, usually have a salad bar or at the very least fresh fruit and veggies i can eat on there own. Otherwise I just eat smart. Since for the most oart, making my iwn food is out of the question. Unless i can bring it with. For day trips, even two days. Its doable.
Personally i try and find a asian/oriental food joint to get a mixed vegetable and chicken or beer stir fry or meal of some kind. Avoiding most salty, unhealthy thick sauces.