Vblake42, yes you are limited to one lake and do have the option of having it moved to another lake, which would be expensive. However if you went to a larger lake there are many marinas that you could move to and explore the lake from each location. There are some lakes that connect to the intercoastal waterway so you can travel a great distance, through many states. But you would need a riverboat type houseboat to do that with. The riverboat houseboats have more engine power to deal with moving water.
Sheila, these pictures are from the bigger and very expensive houseboats. Most of the houseboats are smaller than these, more to the size of an RV. But I agree they are very nice and if money wasn't a problem I would love to have one :)