I also just wanted to mention that the houseboat we had, had 2 washroom, which was awesome. One was the stool room, the other was the pisser. Made life sooooo much easier/cleaner. The toilets were like this, which I found incredible.
The handle on the left of the toilet was an ejector handle. You sit, drop a stool, and eject it immediately, while still sitting the whole time. Made me feel like a real man being able to do that, and it made the whole boat stink free. We also had a policy of puking off the back of the boat instead of the washroom. Not only did it make it more hilarious for every watching from the shore, but less mess to clean afterwards.
I also mentioned in my earlier post that I was able to hook up my turntables to the boat's audio system. Most houseboats now have auxilary inputs on their faceplates, so make sure someone brings an auxilary chord so you can play music directly off of your own music device.