Not a place in particular, but if you're driving, avoid any border crossings during peak holiday seasons. Specifically when you're crossing from the EU into non-EU countries or crossing from Schengen into non-Schengen area. During peak times you might be waiting at the border for hours.
Wanted to say that too. I mean, technically the train network is pretty well connected but it's so underfunded that trains oftentimes don't drive at all or they're late and then every train after that is also late. It's mostly fine but it happens way too often. I had to stand in freezing cold for an hour or longer too many times in the last three years where I took the train daily.
I don't know, maybe it's just particularly bad where I live, but I regularly have to the the god damn Schienenersatzverkehr, and even this god damn fucking bus that is supposed to replace the train is always like 20 minutes late. Like how the fuck do you even mess that up DB? HOW?!
Yeah, I had to take a SEV for a while too because there was construction on the train tracks and I came late every single day because apparently nobody at DB thought that 2 full trains (and with full I mean that people always had to stand because there weren't enough seats) couldn't just fit into one bus. That bus was always completely full (people standing in the middle up to the front door) and a lot of people still just wouldn't fit in.
Well, there are some exceptions. This year, I'm travelling by train to all my holiday destinations, but the last connection I will fly because the trains run in such a stupidly way.
In my case actually Western Europe, but a very specific connection that would either need to go through the alps (which means slow speeds and switching trains a lot) or take a huge detour via Paris.
For driving tunnels in the Alps are the worst. The Gotthard tunnel or the Karawanken tunnel on the first days of the vacation period were the worst traffic I have ever seen.