One quick heads up about kids and houseboats.... If the ship has a generator, keep the kids out of the water around the houseboat while the generator is running... please.
Kid being kids, at least have them move up wind from the boat while they play until the generator gets shut off.
Other than that, have fun, Lake Powell gets in your blood and you won't be able to stay away.
Enjoy the lighting shows (Monsoon season) that time of year as well, impressive.