I have spent a couple winters at Rock Crusher before we bought a house in Crystal River.
Rock Crusher is a very nice park very friendly staff and campers but it is a snowbird park that fills up in winter with lots of of activities and pot lucks.
There is another campground about 12 miles south of Crystal river on the Chassahowitzka river.
This is the river I normally fish out of and prefer to Crystal River ( not as crowded and better fishing and has gulf access. Note you need a shallow draft boat or kayak for this river.
Campground is a regular type campground not a resort style for shorter stays with boat ramp and docks and LOTS of manatees in winter.
ALSO if you camp anywhere near water and temp is above 70 * Noseeums will make you hate camping. One advantage for Rock Crusher.
Not sure how to attach a link but you can find with a quik search.
Chassahowitzka River Campground.
I live in the area if you have any questions