No, we don't travel with our dogs in the bed of the truck, but gotta add my .02 anyway. After 9 years in veterinary clinic work and 27 rescue dogs over our 50+ years, think I've got some input. Glad to hear you plan to crate/kennel your dog....this means you don't get my other unsolicited advice. Suggest you look into the airline type crate. Ventiliation is good. The wire type are fine for home use, but you stand the chance to debris blowing around and getting into the eyes. Most have a water container attached to the door - suggest you add a few ice cubes. You can secure it into the bed of the truck pretty easily. Is your dog used to being in a kennel?? If not, suggest you start slowly at home with some treats and a positive approach. Start with just a short time and work up. Don't recall you mentioning how long a trip you'd need him/her in the crate, but if it's more than a couple of hours, a stop for walk/piddles/other would be good.
Ideally, your pooch could ride in the truck, but if that's not possible, this is workable. If the weather is terribly hot, please come up with Plan B, even if that means leaving him home with someone caring for him or boarding, which I do know is pricey.
Re putting the dog/crate in the TT, not a great idea. It gets hot and stuffy and you cannot keep as close an eye on him as the crate in the bed of the truck.
I know you specifically didn't want input from those of us who don't travel this way with our dogs, but guess you haven't been around long enough to know that when you hit a hot subject, you'll get responses anyway. Hope you're not offended, but primary concern is the health and safety of your dog. I think you can do this safely with a good crate and common sense. Extra tummy rubs to the pooch and happy camping.