I just use the search feature and enter "campgrounds" and the city/town/region. It may also be in the Accommodations section and the town. If it's there, it'll come up. Campers are being encouraged to put their reviews there so others can access it readily. Trip Advisor will let you review the behaviors of the management and staff unlike some of the other RV campground review sites. As we all know, staff attitudes can make or break a camping experience as well.
RVers also like the option of finding reviews of local restaurants and attractions for the place you're visiting at Trip Advisor. It's an all in one. It beats spending valuable time visiting multiple websites for info.