I recommend a tour of the old town and one of Our Lady of the Rocks, a pretty little church in the Bay of Kotor near the town of Perast. Legend states that, at the spot where a religious icon was found in the water, local fishermen would drop rocks in that spot after every successful voyage. Over time the little island was formed and the church was built. You can catch a boat from Perast. Also, the cruise into the Bay of Kotor is magnificent and not to be missed (we did this cruise in 2010). You'll have to get up early to catch it, but I throroughly enjoyed it. Also, what I did not know about Kotor and wasn't prepared for was that the city sits at the bottom of a huge limestone cliff that can be hiked. From our ship we saw people going up and down the cliff face. That was the one thing I wish I'd done that I didn't while there, but time constraints with our scheduled tours made that impossible. Kotor's old town is nice but not on the scale of Dubrovnik, which we visited first. Btw, our tours were arranged by our cruise ship (Oceania), so I don't have information on scheduling tours independently. I hope this helps.