Liberty Harbor is just a parking lot with hookups, but it is a good location for what you want to do - and there are almost no other options in that area!
Suggest you check with www.rvparkreviews.com for info from campers on CGs in Cape May area. Also be aware that there is Cape May, then Cape May Court House, two different towns! Most of the CGs in this area are filled with seasonal campsites, and many were created when rigs were much smaller. While most have mostly level sites, they are almost always very, very close together. I would avoid the KOA in the Cape May area (used to be Lake Laurie CG). They have created a newer section for larger rigs, but their ownership seems reluctant to employ enough staff to keep the place even reasonably clean. If you do plan to go there in July, I would seriously consider making reservations ASAP, particularly if your stay would include days over the weekends. These places are costly, but they fill up fast almost every weekend from April through the end of September.
Two young retirees restless to GO!
Life is too short to wait too long to do all we want to do!!
Go and enjoy!!