Probably not if you pick up a car in one country and drop off in another. I looked into that a few years ago for a Europe trip and it would have added $500+ to the price of the rental. Whereas if you book a train ticket in advance it's often $50-60. |
There are two primary TGV Lyria lines- Paris-Geneva and Paris-Basel-Zurich. There is also a Paris-Lausanne line, but it's not as frequent. https://www.tgv-lyria.com/fr/en |
Antwerp or Maastricht could be possibilities. They might be more off the beaten path than some of the other suggestions. I enjoyed both cities as a kid, but my parents were posted in Brussels so I saw a lot of Europe. |