From Kotor, I joined a kayak tour on the Rijeka Crnojevića organized by Kayak Montenegro.
Usually, you have to drive to Rijeka Crnojevića yourself when doing such a tour. I, however, got a lift by the tour organizer the day before, and was provided a tent (well, sort of) to sleep in. Even though this part of the trip did not go too well (there was some down time due to forgotten keys, and a bit of a setback due to an incomplete tent), the tour as a whole was absolutely fabulous.
In the morning before the actual tour, I got an extra half-hour kayaking tour upstream from the village (where the tour usually does not go). On the "official" tour we went kayaking through water lilies, and followed the meandering river about halfway to Skadar Lake. All in all, the trip was definitely worth the money – especially if you consider the fact that I only paid 5,– EUR extra for the transfer and tent accommodation.