JJ,
I live very close to you, and our family has traveled to many campgrounds in the area.
One or two thoughts-are you planning to tow a car? If not, site seeing takes a bit more planning, although you can also Uber, or use the rv as your car Also, for a first camping trip and looking at 4-5 allotted days, I would suggest sticking closer to home than New England. Just my opinion.
I see that you are from Perkasie. I believe that Fretz RV rents rvs.
Otter Lake is in the Poconos and is a great place to go to relax and swim. It does have a lake, but I am not sure if you can swim in the lake. However, Otter Lake also has a swimming pool, planned activities, and is a great place to ride bikes. It is not that close to any other things to see. It’s a bit out there in the woods. Not that you can’t go anywhere.
Lancaster is also a fun place to go. You could stay at Old Mill Stream and head over to Dutch Wonderland (although who knows about that with COVI 19). Old Mill Stream does not have a pool or much else that kids would like, but it is very close to other activities in the area that your family might enjoy. Lake-in -Woods is also in Lancaster and more of a campground that you could go to and swim, ride bkes, etc. If I recall there is also a lake (again, not sure if you can swim in it). Maybe miniature golf (check the website)? And, it too, is a bit farther away from Lancaster activities.
Ricketts Glen has a lake and great hiking, but I don’t think there are any hook-ups. Again, might not be a good idea for first time campers.
Knoebels has a campground, and there is another very nice campground nearby (J and D), but again, COVID 19 might make this a wash.
Hope this helps.