My review still stands but I wanted to add a tip to the previous review.
First off. If you look in the internet it lists the place as closing at 4:30pm. That only applies to the Visitor center and not the hiking grounds and scenic drive.
Those are open earlier and until dusk each evening which on a day in the summer is more like 8pm or so.
Also. A quick update as of May 2018. The price for a single vehicle was increased from $7.00 to $15.00. Its a bummer but the price is still a great value.