Oh little cutey! Try not to worry, he'll be fine, Annie....
We had an epic 7 hour trip plus the worry of snow... But the little one took it all in his stride. He sat on the OH's lap in the front passenger seat with a towel and blankie. We stopped part-way for a 'comfort break' - I fed him and he had a little water then whilst we took it in turns to skate across the car park to the 'facilities'

, he was placed in the footwell with lots of newspaper where he obliged us by performing 'wee-wees' and 'get busy's' Several vehicles pulled up by us with grown dogs on board to let them out so I didn't want to put him on the grass, just in case. And it was far too cold to put him in the boot in his crate as originally planned to let him scoff and toilet as the wind was Arctic
We took towels, wet-wipes, kitchen towel, newspapers, pooh bags and plastic bags. A flask of hot water to dampen his kibble (it soon cooled down!) A couple of little bowls for his food and water. A few toys, one to chew on and a puppy-sized furry one to cuddle up to. And his fluffy blankets. We had a change of clothes for ourselves as we went overnight, Oh, and I took his collar and lead but in the event, he didn't leave the passenger seat.
Apart from the occasional attempt to springboard into the back seats off the OH's belly, he was perfectly content to sit and snuggle, or look out of the window, or lick my husband to death... Try not to stress about your journey, just see it as part of the whole adventure and you'll be fine. At least you'll get to cuddle Yoshi... I had to do all the driving, so no cuddles for me!
We popped him in the garden, but not for long as it truly was freezing, and I didn't want him to get cold.
One tip - I've used a lead to take him out in the garden for his toileting and the bloomin' clip was
so stiff! If you have a lead, spend a bit of time now, working it so it'll snap on and off easily... Oh, and I have a snap buckle collar for Wyre as Ianto would never stand still to buckle his on!
Phew!
And a Mars Bar....
Anne, Ianto & Wyre x