Joining a tour on Day 2 but have Day 1 to myself. Any nice spots to check out that tourists don’t know about?
We especially enjoyed this museum the home and studio of an artist. https://www.visitljubljana.com/en/poi/plecnik-house/
Easy walk ftom the center of the city.
Second the above. We really enjoyed it.
We spent a good part of one day in Tivoli Park before finding a nearby brewery for an early dinner.
Take a walk down to Park Spica towards the evening and hang out on Eipprova Ulica. (These are also close to Jože Plečnik museum.) Sax bar has great live music.
Skip the boat tour. I’m betting your tour includes a Ljubljana walk. Some of these hit the castle, marketplace, etc. If it does, I would highly recommend taking the “Communist Walking Tour” (look online) which not only tells Slovenia’s story under Tito, but takes you around a less touristy bit of town.