The property is fantastic...pristine pond, cabin, grounds, trails...you name it. We traveled with our two children and a dog and had a great time. We fished, hiked, rock hunted, panned for gold, cooled ourselves off in the creek and had an overall great time. This was the first time my young children fished and they caught a ton of bluegill and bass. As an experienced fisherman I found the bass fishing exciting (just about every bass we caught was a good size and I saw a couple monster bass swimming around) and I also caught a couple nice sized catfish. The trails were fantastic for hiking - if you go in the summer it is common sense to bring quality bug repellent. The driveway to get down into the valley has ruts from frequent rain and a significant drop on one side - we had an AWD vehicle with higher ground clearance and had no issues however I wouldn't recommend a standard sedan, etc. as you may drag the underside at some points.
We live within 45 minutes of Hidden Valley but I can tell you that once you are there you totally forget where you are. I left like I was in southern Ohio somewhere near Hocking Hills. This place is fantastic and we are already planning a return in the near future.