Just put them in a Coleman cooler..it'll keep them cool a long time. Duct tape the lid shut.
uh...yeah I'm joking, but I guess I grew up different. Dogs were hunting dogs and not much sentimentality attached to them. My Dad and uncle did field trials and if the dog didn't perform it was gone. Don't bother getting attached to them.
But I do think dogs are more tolerant of conditions than is being worried about here. I can remember Dad putting them in the "turtle shell" of his 1953 Chevy, finding a sandy country road, tying the dogs to the bumper and exercising them before hunting season. In August and September in south Texas.
There are likely several hundred thousand dogs within 250 miles of me laying around outside in 95 degrees the shade all summer.
Put them in the trailer crack a couple windows and give them some water when you stop.
2018 Ram 3500 Laramie CC DRW LWB 4X4 Cummins Aisin 3.73
Reese Goosebox 20K
2018 Heartland Landmark 365 Oshkosh
2008 Bigfoot 25C9.4 LB Cabover