Where to??

Hi all! My fiance and I are getting married in August of this year but we are pushing our honeymoon to summer 2025 because of our work schedules, so we are still in the very early planning process. We know we want to do Europe for roughly 2 weeks, but we are struggling with where to go! I think we largely want to travel by train and would ideally like to visit multiple countries. Considering places like Holland, France, Switzerland, Italy… anyone have a decent itinerary like this? Is 2 weeks enough time? Too much? Any help is appreciated! TIA!