FINALLY! It seems that some have figured out that this is a question that needs to be addressed! According to The Blaze:
The Obama administration is considering allowing some national parks to be maintained by states during the partial government shutdown, but is still withholding information from Congress and the public about the cost of closing so many open-air monuments and parks.
“It would appear logically that the cost of barriers and security could cost more than simply leaving open,” House Natural Resources Committee Chairman Doc Hastings (R-Wash.) told TheBlaze. “We’ve asked the National Park Service and unfortunately we haven’t gotten answers.”
The Natural Resources Committee and House Oversight and Government Reform Committee will hold a joint investigative hearing Wednesday on why 401 national parks and monuments were closed across the country during the shutdown.

As an avid outdoor enthusiast, I have a great deal of respect and fond memories of my interactions with Park Rangers.
Vacation. The time to let go, relax, and enjoy the scenery. Go where you want, eat what you want … no, wait, can’t to that anymore.