My husband and I stayed here with our two dogs for a week. Twin Grove is one of the few campgrounds on the eastern side of Pennsylvania that has running water in early April—but that's not all they had! The campground itself is huge with a good number of pull-through and back-in spots for RVs and a large number of cabin for rent.
The location is conveniently off of Interstates 81 and 78 and it's set back just enough that you don't hear a whole ton of traffic when you're trying to relax. My only advice is that if you are going to stay for more than a couple of nights, hit up the the grocery stores in Lebanon before you arrive because it's quite the trek into town for real groceries.
There is what appears to be a full amusement park for families to keep their children entertained. Whether it costs extra or not, the sheer number of activities is enough to keep most kids busy and that should keep most parents happy. This includes a few playgrounds, a carousel, a pool with a water slide, an ice cream parlor, and many other activities.
The bath facilities were warm and clean, but the showers fell short of even standard expectations with painful water pressure, very dark lighting, and faucet fixtures that were hard to turn off, on, and set temperatures. The laundry room was clean and the machines were in good working order. The number one reason why we are likely to return time and time again, though, are the two massive fenced dog parks they have available for their furry campers.
The wifi was excellent for a campground and while it wasn't as fast as a private connection, it was very good for the standard working adult to keep up with the goings-on at the office. Verizon cellphone reception was also excellent in the area.
Overall, we had a great stay and will be back for another week the next time we pass through!