Question Best 4-Day Train Itinerary from Budapest to Prague?

I'm planning a 4-day journey by train (and maybe bus) from Budapest to Prague and looking for the best itinerary. I want to make the most of the trip, so I'm interested in scenic routes, interesting stops along the way, and any must-see towns or attractions. Has anyone done this route before? Any recommendations on where to stop, how to split the days, or tips for train travel in this region would be super helpful. Thanks in advance!