Driving from UK to Greece

Help! I've checked the gov.uk website for advice on driving to Greece next month via Slovenia, Croatia, Serbia and Macedonia. It gives me facts but not a feel for what the actual experience will be like. To compound this I'm travelling with a dog, and it doesn't give any advice on any additional considerations there may be. She DOES have her full UK pet passport and all required inoculations.

Has anyone done this journey recently....say the last 12 months?

Thanks in advance :)