Do I need to make a separate campsite reservation

Yes, you almost always need to find your own campsite reservation, but that can be negotiated with the RV owner. The campsite fee is paid separately from your RV rental through RVPlusYou unless you have made arrangements with the RV host. Some campgrounds are first-come, first-serve and your RV host can advise you how to best to secure those sites. Other campgrounds book up months in advance and require reservations well in advance.