I'll start off by saying that Krka Falls and Plitvice Lakes are by far the most touristy and controlled national parks I've ever been to. So if looking for an adventure, this is not the place to have one.
The day started off with a complementary breakfast at Fife, which has average food. We then took a bus to Krka Falls. On the bus, our tour guide gave us a bunch of historical facts about Croatia, but her English was hard to understand.
When we arrived in Krka, we had the option of following the tour group or going off on our own. Regardless, you have to take the same path because you can only go in one direction in Krka. There are no detours, just one main path that everyone follows, and there are so many tourists that there will always be someone in front and behind you.
The first 90% of the path isn't anything special, looks decent but nothing memorable. At the end there's a portion of lake where you can swim. It's cool to be able to swim in the lake, but there's a rope about 30 meters away from the waterfalls, so you can't actually get near them. And on the last stretch of the path, you can get a bird's eye view of the waterfalls. This is the only sight that I would consider extraordinary; however, if you want to get pictures, you're going to have to hold up a massive line of people behind you.
The tour ends with a bus ride back to the main bus station and some more historical facts.
I'd say this is something you should do, just to say you've been, but don't expect to have the time of your life. It might also be a better idea to rent a car and do it without a tour instead.