I'm really jealous that you're doing this trip! Sounds like you had a good drive today.
I did the Staples2Naples banger rally a few times, starting in 2008 in a knackered 4-Litre Daimler XJ40 and it sounds like you're doing the same route so far, in the same chunks.
The second time we did it, we picked up a pair of young Dutch girls who were doing a hitchhiking competition out of Calais, to get to Luxembourg as fast as possible... We were planning to get to our first day checkpoint in Sarnen, Switzerland by just booting it down through France, but seeing as these two lovely ladies wanted to get to Luxembourg ASAP, we changed plans and took the 5 countries route. It was a heck of a drive (as I'm sure you'll now agree!!) but so much fun. We got them there some three hours ahead of their competitors and in the lap of luxury.
My favourite bit was the passes in the Alps - The Grimsel and the Furka - just epic roads to drive. Second favourite was driving in Italy - the assertive driving style takes a bit of getting used to but it was a huge blast to hustle a big luxury car through such a beautiful country.
If you get bored, you can read about our exploits here:
http://teamxj3.blogspot.com/2006/09/...coquelles.html
Jolly good luck with the trip and please do keep us posted!