I tend to run up North more in the Summer. Of course I have to come home every two weeks or so. I found a good deal on a brand new Thermoking I have, yet, to install. I should get that done within the month, before it gets too hot in texas.
I use to work for TMC and they don't like idling much. Plus, you got extra point for your pay if your idle was low. Mine was usually at about 4%.
I've tried everything. Fans are a must, sometimes a couple. The turbo fan, works, but is noisy and breaks every few months. The fantastic fan is a must. You can hook it in front of your opened window and it will draw the cooler night air into your sleeper, then have the turbo fan blowing on you, it makes it tolerable.
Get the windscreens. The offer some security and allow the cooler air inside, while keeping out the bugs.
They make an airconditioner of sorts, it has a bin to put ice in and a fan blows or suck air across the ice. It works somewhat, until the ice melts, which doesn't take long. So you will be up several times during the night going inside to buy ice. It has a misting function on it. That does keep you cooler, but you will wake up with a soaked bed. I wouldn't use one again.
You can keep a wet face cloth handy, get naked and wipe yourself down all night. That has, obvious, disadvantages.
Plan your driving so you are sleeping in the coolest part of the day. Run your A/C to get your sleeper cold before you stop. Hopefully, you will get some rest before it gets too hot.
Take a shower before going to bed, maybe don't towel off as thoroughly as you normally do. Just being clean helps me sleep better.
Find a good set of the reflective sun screens. They will lower the temerature in your truck considerably.
Park in the shade.
Park so you have a good breeze coming in through the windows.
Drink a cold drink before you sleep, it will cool your insides. You'll have to get up to pee, but it works somewhat.
Sleep on something that doesn't reflect the heat back onto you.
Just a few ideas that work for me. Can't wait to install my APU, though!