We just spent our fourth winter at Rock Crusher and yes, many people leave their RVs there year round in a site. It's not cheap though! You end up paying about $5800. per year in addition to other monthly fees when you're on site. If you want to leave the electric hooked up when you're not on site, so you can keep the a/c working (needed to prevent mold and mildew!), then there's an additional charge.
Rock Crusher was sold to Sun RV Resorts in the summer of 2015 and they are making some changes, including moving in a few park models thus cutting down the number of RV sites which will be available out of the 398 sites in the park.
Sun RV Resorts own parks all over the country, so you might find one in the area in which you are interested.