Let's say we're heading north from Split, Croatia.
A few days car rental to explore Istria, Plitvice, the lakes of the Julian Alps & Škocjan Cave
would be the next phase of the itinerary.
After returning the car, we'd want to take an overnight train to Budapest.
Where would (or should I say how far South could) one base this car trip
to then easily get to Budapest the morning after?
Here are the problems:
We'd have to take a train or bus ride to get up to Zagreb, or most likely Ljubljana, to then rent a car to get back down to Istria near to where we were.
The night train from those towns is a doable 11 hours.
If we just take off by car from Split or Zadar the night train is around 17 hours (actually more from Zadar believe it or not.)
We've never tried a train ride that long.
Do they let you stay in your sleeper car until the early afternoon?
Folks have stated that Eastern Sleepers are not as plush as Western.
Will we be miserable after nearly a full day in one?
Finally, we will have a European East Pass which doesn't include Slovenia/Croatia.
Will the single ticket cost much more from those coastal cities than a Capital city nearer the border?
And will we even use our Eurail Pass for this segment if we started outside but ended inside our covered area?