I have a canvas canopy over a steel mesh frame and when we first went north it heated up quickly compared to my old steel canopy. In an effort to keep the fridge and food stuff cooler I lined it with Foilboard, which is a 7mm foam sheet with a thin reflective foil on both sides. You can certainly feel the difference. I am lucky to live reasonably close to the factory so it wasn't a hardship to get some.
I also have some vents in the front of the canopy, which certainly helps keep the dust out, but obviously lets the warm air in. I believe that it would stop a non vented canopy from getting to extreme temps though.
As far as your food goes, we have had a few trips up into warm to hot weather for up to 3 months, and we haven't lost any tucker due to spoilage (touch wood). Of course anything that needs to be refrigerated like meat, fresh milk, some salad stuff, dips and spreads, some containers once opened, and at least a dozen beers are all in the fridge, but things that would normally sit in cupboards at home we keep in a crate.
Extra beer, long life milk, etc sits in an uninsulated crate and gets swapped in the fridge as we use the stuff already in there. Groceries are uninsulated as well and get used when needed. About the only thing that takes a beating out of the fridge is the bread. Not a lot you can do there when you take it out of the packet to make a sandwich and watch it dry out before you can spread anything on it, just like a toasted sandwich i suppose.
By the way, the steel canopy was powder coated and from memory was never too hot to touch, as Glen said.
