If you are planning a 1 to 2 day SR-20 trip, the main mistake is treating “North Cascades” like one rule set. North Cascades National Park has no entrance fee, but nearby forest trailheads often need a parking pass. Overnight trips use a separate permit system, and access can change independently on SR-20, Cascade River Road, and the high trailhead zone east of Diablo

If you are bringing a dog on an SR-20 trip, the main problem is not “finding a hike” - it is picking one that stays on the right side of the boundary. This guide filters to dog-legal options along the corridor, plus the two detours people actually do on the same trip (Baker Lake Road and Washington Pass trailheads).