Do: Any hike in and around the Diablo area of the Park, which (supposedly) offer excellent views of the Cascade Mountain range. Widespread smoke hampered this experience, however.
See: Towering Cascade Mountain ridges along the road as you head northwest deeper into the mountains.
Drive: Highway 20 between Marblemount and Diablo offers gorgeous forest views and striking mountain vistas, and the hydroelectric plant near Lake Diablo is an interesting sight along the road.
Stay: Newhalem Campground offers a number of fairly secluded sites on three large loops, and appears to be centrally located in the park. Backcountry camping also seems exceedingly popular, but only when wildfire smoke will not suffocate wayward hikers…
Eat: The biscuits at Joy’s Sedro-Woodley Bakery, located in the town of Sedro-Woodley, roughly an hour west of the Park, and it appeared their other baked goods were of a high-quality as well.
This Is Your Brain On Parks 