In about two weeks I will be visiting Zagreb for two days.
As I have already been there (four years ago) and as the city is quite small I was thinking about maybe making an excursion one of the days.
I had a look at a map and found that the Slovenian capital Ljubljana seems to be pretty close to Zagreb.
I have never been to Ljubljana or Slovenia so it would be fun with another country to add to my list, I have also heard it is a very nice city and not overly touristic which I appreciate.

Does anybody know how far it is from Zagreb to Ljubljana? Is it possible to go there as a day excursion?
What would be the best way to get there? Train, bus? Any idea of what price to expect?
My hotel is located next to the railway station (have a reservation at the Regent) so a train would be very convenient.

Any tips or advice are appreciated.
Thanks!