I'm a little late to this thread, but my understanding is that OC and CC (with CCW permit) is legal in both National Parks and National Forests, with the exception of buildings. For example, weapons are not permitted in the Gladie Welcome Center in the Gorge area.
The Fair Credit Reporting Act had an amendment added to it that basically said all NPS land would follow the state law in which the land was located with the restriction of except structures where federal employees normally worked - signage is required for these buildings.
http://Section 512 carried the titl...s to the national park system outside Alaska.
National Forests
not included in that law and are other restrictive details.
Laws Regarding Firearms on National Forest Lands
First, the primary laws governing possession of firearms and other weapons on National Forest are State Laws. These laws were developed by the states following establishment of our Cooperative Wildlife Management Agreements. Most notable of the state laws concerns controlling firearms on the National Forest are “cased gun laws”.
Cased Gun Laws: As the name implies, this law requires that all firearms on National Forest be unloaded and kept in a case. Virginia and West Virginia have similar “cased gun laws”. In order to allow hunting, these laws make an exception.
• It is legal to have loaded firearms on National Forest during the authorized general firearms and muzzle loading gun seasons for bear, deer, grouse, pheasant, quail, rabbit, raccoon, squirrel, turkey, or waterfowl. This exception is very specific and applies only during the period when it is legal to take these listed species and doesn’t include carrying the loaded weapons in a vehicle.
• Because hunting on Sunday is prohibited, carrying a loaded gun on National Forest is not legal on Sunday even if it is the Sunday in the middle of the general firearms deer season.
• The second exception to this law allows people with a concealed weapon permit to carry a loaded, concealed, handgun either on their person or in their vehicle while on National Forest. This does not apply if the person is engaged in a primitive weapons season or chase only season.
• People muzzle loading or bow hunting may carry a concealed weapon as long as they possess a concealed weapon permit.
Discharging a firearm, crossbow, or bow and arrow in or across a road or within the right-of-way of any road is prohibited by both State and Federal Law.
Any person convicted of a felony may not legally possess firearms on National Forest.
Reckless use or handling firearms: It is a violation of both Federal and State law to handle any firearm in a careless and reckless manner or hunt while under the influence of intoxicants or narcotic drugs.