I am a long time hirer, and over the years my wife and I have done various canals. We've never done the K&A (despite it being the closest canal to where we live) and read the OP's comments with interest. We did a week on the Shropshire union/Llangollen canal a few weeks ago, and I happened to encountered two separate boat owners who had cruised the K&A earlier this year. They were both unimpressed with the K&A, with one of them mentioning that in their opinion the Western end had far too many liveaboards and the other mentioning that to their surprise the canal is overgrown and shallow at the edges in places. They both mentioned that these factors make finding a place to moor harder than it should be.
jradley I would highly recommend you do another holiday on a narrow canal......your wife will find the narrow locks much easier to work than wide locks. I would also recommend you don't really set a strict schedule.......if you are on a 4 day hire just see how far you get in 2 days then turn around. This makes for a much more relaxed holiday.....especially when you encounter unexpected minor stoppages, which happen more than you might think. (We've been stuck at a lock for 3 hours because a tree branch was stuck under a paddle stopping it closing, and on our last trip an unfortunate hirer sunk their boat in Wharton's Lock on the Shropshire Union....it took 2 days to clear it). Sometimes locks get congested and it might take an hour or so of queuing, so a schedule can just add stress.