Extra day at end of RS Central Europe (fka Eastern Europe) Tour?

Extra time in Ljubljana would definitely be worth it, IMHO. It's a pretty, very walkable city that is worth some extra time. You could also take a day trip or two to see more of the surrounding area, which is filled with interesting sights and beauty. I was there on the Adriatic tour and it was a highlight of the trip.

We just did the Central Europe tour last month, and we spent an extra two nights in Ljubljana at the end. Definitely worthwhile -- it's a wonderful small city with a fun cafe/restaurant scene along the river. We took a day trip to Postonja Caves and Predjama Castle on Monday...absolutely amazing and we highly recommend it. We booked it with a tour company and it was about an hour away from Ljubljana.

I took the Eastern (now Central) Europe tour two years ago and it was great!
However I may be an outlier, but I didn’t feel the need to spend any extra time in Ljubljana. Don’t get me wrong, it was a cute, small-ish city, but the afternoon we spent there on the tour was enough for us. Not sure what we would have done with an extra day there. There aren’t really a lot of sights, but probably if you like relaxing at cafes, etc, it would be a good fit. Not necessarily a bad thing after such an active and amazing tour:)

We did this tour 3 years ago. We regretted not flying out of Ljublijana and spending an extra day hanging out in this city. Instead we took a train to Vienna, spent an entire day on the train, got to the Moxy at the airport and had to leave at 5 am the next day on our connecting flight through AMS. It would've been smarter to fly out of Ljublijana and spent the day there instead of on a train. We also learned we could've easily made an early connecting flight from Ljublijana the day after the tour. The hotel was wonderful to line up cabs for those departing on those early connecting flights. Cabs in Lake Bled were very dependable. Prior to the tour, we were familiar with Vienna but weren't sure of Ljublijana. After spending a day in Ljublijana on the tour we learned it's a wonderful city--so many fun cafes, bars, market, sites to see--all easy walks. This tour is great. Have fun.

I haven't taken the Central Europe tour, but I did go to Ljubljana on the RS Best of Adriatic tour. I arrived in Ljubljana a couple of days before the tour started. I found it completely charming and delightful!. If you are flying out from there, I'd say it's worth staying a day or two. It was a relaxing place to recover from my jet lag, so may be a nice place to unwind after an active tour. I mostly recall strolling the pretty streets and relaxing at a cafe overlooking the river.