<human>: Summarize the given text in a few sentences.

Alright, to start this off, my girlfriend and I just got back from a trip around Ireland where we were there for 12 days and stayed in 3 city's for 4 days each. A small town, a medium sized city and a big city. We rented a car and had a map with a wide range of points of interest on it. We decided the day before where we would go depending on weather and how tired we were. We really enjoyed this style trip and would like to do something similar somewhere else. 

We like history, architecture, and beautiful scenery. Night life is cool but not mandatory.

Alright, there is the back story, thanks if you read this far in.

This next trip should be between 15 and 20 days including travel from the east of Canada. 

So right now I'm deciding between a very similar trip around Italy staying in the south, middle and north. Sticking to one country was fun and we learned a lot, but I'd like to see more if it is reasonable.

 Or a trip starting in Croatia, staying there for a couple days in a couple different cities(no idea yet what to see or where to stay). Maybe heading to Venice, maybe not. Travelling up through Slovenia, Austria, Germany(maybe Munich stop over for a couple days, no idea) and ending in Zurich, Switzerland. I have no idea about what I should see or if I should stay a bit in Slovenia, or Austria or even Germany or Switzerland. 

I would be free for an March/April trip. 

Is there a thing you would change? I'm open to pretty much starting anywhere and ending anywhere, this was just a preliminary idea to run past some fellow travelers.

Is it even possible to rent a car in one country and leave it in another? should be use a train between the countries? Plane?
<bot>: Idea for a trip, Croatia-Slovenia-Austria-Germany-Switzerland. Good or bad idea?