I think I got up to 80km/h on the faster bits (especially that almost straight bit where the half-tunnel is).
I don't live there, but I really wish I did. I live in Melbourne, Australia, where anti-cycling prejudice is every bit as bad (or worse) than in the UK or USA. Yes, I have a French phrase in my CycleChat signature line, but it's just wishful thinking.
80km/h is a good clip. That’s about 50mph. To me, that’s fast. I would love to experience what you did.
Unfortunately there are but a few countries that one would say are bike friendly. Parts of the US are where they have developed a decent infrastructure, and I will say, here where I live many roads have bike lanes, but still, so many drivers are just rude and nasty, especially those who we refer to as rednecks. They drive around in loud pickup trucks. Last year, my city was voted number one redneck city in America.
You mentioned how you would like to live in the area that you visited. I’ve never been there, but I’m sure I would as well. Anywhere that has drivers who show a respect for cyclists.