Try Hocking Hills in southeastern Ohio. Lake Hope state park has a beautiful lake and nice cabins. Tons of hiking and biking trails through pretty much pristine forest(Zaleski National Forest) and rock formations (Old Man's Cave, Cedar Falls to name a couple). Other options would be the numerous B&B's in the area. Very popular part of the state for vacationing so accommodations may be tough to come by but definitely worth a look. I've spent many happy times there since I was little.