We did the Bus+Walking+Boat tour. The tour itself is very enjoyable (if weather allows), the walk is not particularly strenuous but long (11+ km), but you get rewarded with a few absolutely gorgeous views that really pay the effort. The boat part is also pretty stunning, as you will be immersed in an almost unspoiled environment, with the boatman giving nice hints of where to look and of the history of the place.
My only complain is about the bus that brought us to Kate Kearney's college, as it was very late and left us there at 10:45. The boat would leave at 2 pm with or without us, so we basically had to rush for the whole walk, which made prevented us to stop anywhere just to gaze at the landscape for a while.
Another oddity is that Kate Kearney's cottage would only open at 11, which is too late if you want to walk. Luckily there's another café where you can buy food and drinks for the walk.
Finally, a word for those who want to do the tour by car: please don't! The road is narrow, you will have a hard time whenever you face another car, a jaunting cart or even just walkers! You won't either be able to stop at will to admire the panorama. If you don't want to walk - which I'd recommend unless you have difficulties - take the jaunting carts, you will enjoy this corner of Ireland much more, trust me!