Watoga State Park is beautiful. It's the perfect place to stay while exploring the area. No Verizon cell service within park, but wifi is available at the campground check-in stations at both campgrounds and the visitor center. Beaver Creek Campground: basic shower house (what you'd expect for a dated facility), convenient dishwashing station. Campsites between the check-in station and shower house offer little privacy but some are within range of the wifi.
Take advantage of the dark skies to do some stargazing.
Pack carefully. It's a drive to big box stores. Plus, with so much great hiking, you don't want to waste time driving to buy forgotten supplies. :)