I take the dog on summer holiday every year, but to Italy which has specific dog beaches and even supermarket trollies for your dog as it's simply too hot to leave them in cars for a short time. It's a very dog friendly destination.
I usually take him for a good morning walk before the drive to tire him out, then I line the back seat with old towels and put the dog bed on top. He has a harness that clicks into the seat belt so he can't move around too much or distract the driver. (it's the law in our country anyway).
Plenty of stops on the way for water, toilet and sniffs. I keep a bag behind the seat to save digging around in the boot with his leash, dog sacks, travel bowl, travel water bottle, kitchen roll, snacks and food if needed with the timings.
I weigh out his food and bag it at home to cover enough for the trip. I usually make up a Kong with frozen yogurt to keep him distracted in the car, but he usually sleeps or enjoys looking out of the back window.
I check the accommodation to make sure there is a gated area if there's outside seating, eg in a mobile home, so that we can relax when we sit/eat outside.
As their routine is a little thrown, you might find that they don't eat at their usual times, but I try to still ensure it's the usual routine where possible to put food down.
A couple of spare tea towels are useful to rest bowls on, so he doesn't make a mess on the floor. I also take one of those dish brushes you fill with washing up liquid so we don't use the same cloths etc to clean the bowls, and it's nice and transportable in a zip lock bag.
And of course his favourite tennis balls and soft toy.