Big difference between Parker and Lake Havasu. First and foremost, are you dragging a boat along? Parker is little boat water. It can be done with a bigger boat, but isn't alot of fun if you don't know the area due to shallow areas.
Havasu is big boat water. There are lots of choices of where to stay there, and that's typically a slow time of year. Places such as the Nautical Inn or London Bridge Resort are right down on the water and would be a good place to start.