I'm in the transportation planning business and I would recommend sending comments via the project website (http://www.wsdot.wa.gov/Projects/SR14/MarbleRd/feedback.htm) with specific details about recreational uses of Ozone. Also, the WSDOT will need to know the exact location of the parking area. The parking area for Ozone is likely located in the right-of-way for SR14, so WSDOT should know that cars will be parked in this area. The worst case would be that WSDOT would turn the parking area into a new storm water treatment facility (open ditch) which may cut back on the parking area. Also, if Ozone is indeed located on NPS land it may be considered a 4(f) property, which is "any publicly owned land from a significant public park, recreation area, or wildlife and waterfowl refuge, or any land from a significant historic site." I think under 4(f) WSDOT couldn't limit access to a recreation area, but this may be a weak argument since the parking is on WSDOT right-of-way and Ozone is not an "official" recreation area.
But anyways, send comments to WSDOT if you can't make it to the public hearing. Remember, try to be as detailed as possible in your comments; project scoping is not a democratic process, but a method for WSDOT to hear issues from the public that weren't raised during the inital project development.