Robert,

It's exit 107 (Tower City/Tremont) on I-81, then Rt 209 south. It's 45-60 min South of the exit for Paragon (where we were last year).
Here's a link RC directions

As for water, when I'm going to be there several days I take a 5 gal container for cleanup, etc. I'm sure someone at the park will be able to direct you to some water to fill a container at a nearby location. There are some small towns nearby.
I stop for gas at the exit right before (going North) and gas up and fill my water container, than go the back way from there.

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I'll be up there several times between now and then, I'll see if there's any water source park adjacant.

Broderick