Don't know about you but I love day trips except for the part where you have to eat in a restaurant (which you can't do any more). Restaurants are expensive and most of them only have Take-out right now. So what are you going to do?
Why not bring a picnic with you? All you need is some kind of thermo bag or box to keep things cool while you drive (helps prevent food poisoning) and a basic picnic basket. Of course, if you are going to have more than one meal on the road you might want to invest in some bug protection as well as the other stuff.
Start with the thing that says you are having a picnic a blanket and a ground cloth or my preference a pretty plastic cover for a picnic table. Cups, plates & tableware and you have the base.
Food wise you are going to want things that travel well. Pop or Juice boxes or some other bottled drink are a good choice as you know they can stand up to a few bumpy roads. Sandwiches are not a good idea unless they are in a plastic container that will keep them from sliding around or better yet bring the pieces in separate containers and make 'em fresh when you get to your eating place. You can do the same for salads. Coleslaw, potato salad or macaroni salad in a plastic container or for a green salad keep the fixing in their own separate containers until you arrive on site.
The same goes for any other foods you might be bringing. You can get plastic containers that will do the job at a dollar store. The cheap ones come in sets of 10 for a couple of bucks. If you want something that will last more than one trip then invest in the Tupperware type containers. Again you can find them in sets at a dollar store.
Dessert can be anything but I usually bring fruit just cause I like having my daily five. Fruit is also easy to transport because it doesn't usually require a special container.
Finally, make sure you bring a garbage bag and that you clean up your area before moving on.