I suggest you check out Mountain Creek in Vernon/McAfee, NJ. That is in NW NJ.
The name of the time share is The Resort Club at Minerals Resort and Spa and Northeast Vacations Inc. at Minerals Resort and Spa: Interval International Codes, GGR and GG1.
There are also time share units at Minerals Hotel & Spa at Crystal Springs Interval Code SPS
Minerals is kid friendly. It has a very big outdoor swimming pool
Also a heated outdoor pool and a non heated indoor pool. Also a spa and st4eam room.
If your grandchildren are old enough, they can jump into the outdoor pool from a cliff that is between 10 to 15 feet high. Kids love that. The pool always has several lifeguards. The pool has an outdoor restaurant and bar. The hotel has an onsite restaurant (Kites).
There is also a spa and very good gym there.
I believe they have kids' activities at the complex.
You can go hiking to the top of the mountain.
There is a mountain top lake with canoeing and swimming that is part of the complex and that you can drive to.
Restaurant Latour is a few minutes away and is an upscale very good restaurant.
The Appalachian Trail runs through the area and it is a nice and not too difficult hike.
Vernon is less than 15 minutes Warwick, NY, which is a pretty town.
There are very good restaurants in Warwick.
Between Warwick and Greenwood Lake there are often concerts and fireworks on weekend nights.
There are a lot of farms here and you can pick your own fruit and vegetables.
You can go horseback riding across the road from Minerals.
Your grandchildren will love Mountain Creek Waterpark, which is a few minutes away. It has a big wave pool and some pretty good rides/activities.
Your grandchildren should really like Minerals. Your family should be very happy visiting you there.
The units that you get at the resort club are condominiums. The rooms are Meh but because the units are built on a mountain that is used for skiing and snowboarding, the views from the rooms are often excellent.
Minerals Hotels is a hotel room, so I don't think you would have enough room there.
If you want to travel a little further distance, you can drive to the Delaware Water Gap. (Mt. Tammany in NJ is a nice hike). Columbia, NJ has a wolf sanctuary that your grandchildren and you will enjoy.
My children and their friends loved coming here for skiing and during the summer.