Check out Lake George RV Park. We go there almost every year with kids and grand kids. They have cabins and almost any activity you can think of - including evening entertainment included in the price. However, THE PRICE AIN'T CHEAP - $77/night for 2.
When you consider that when you get there, any other costs are discretionary, it's not as bad as it sounds at first look. All sites are 50a, cable, w/s and wi-fi included.
It enters the bike trail between Lake George and Glens Falls. 4 miles on the paved trail to the beach on the lake.
Good luck.
