Be sure to go to Homosassa wildlife park https://www.floridastateparks.org/park/Homosassa-Springs . You can't swim with manatees there but you can see them and other animals.
Aside from Rock Crusher there's a couple of other rv parks right in Homosassa; never stayed in them but they're popular. If you don't have a toad there's an Enterprise in Crystal River. There's also supermarkets, Home Depot etc.
There's not a whole lot to do that isn't water-related; a week might be a bit much.
Also, it gets mighty chilly in January and February.