First, I would hit the coast as soon as possible – take 20 to Ft. Bragg. I would take 5 to 20 and then over to the coast -- by that time, the fires near Clear Lake should be out. By the way, stop for sandwiches at Granzella's in Williams, where 20 hits the 5.
Near Ft. Bragg, there is great boondocking in Jackson State Forest. It’s not free, but it is terrific. Great mtn biking in Van Damme and Russian Gulch state parks – great hiking on Mendocino Headlands. Good mtn biking on fire roads in Jackson State Forest – not right on the coast, but in the redwoods. The Haul Road at MacKerricher State Park is a good mtn bike ride, too, as is Big River just south of Mendocino. Smoke will not be a problem on the coast -- the wind is almost always from the west.
North of there, you can get to Mattole State Beach, a BLM campground, via Mattole Road out of Humboldt Redwoods State Park. Good beach hiking out there. Great riding on Mattole Road in the Redwoods. Riding on Avenue of the Giants is good, too.
North of there, don’t miss Prairie Creek State Park. Great riding on Newton Drury Parkway and on the Coast Trail. James Irvine Trail is our favorite hike in that area. Not too much boondocking in that general area, but Elk Prairie Campground is very good. You mention reservations – most of the public campgrounds on the coast have about 40 percent of their spaces as first come first served. If you arrive right around mid day on a weekday, there is a very good chance you will get a space. Weekends are a zoo, so we tend to stay put and switch campsites on other days.
North on the Oregon Coast, we found everything to be kind of crowded, but the seafood is amazing almost everywhere. Much better than in Calif – I am not sure why. Clams in garlic sauce, crabs at Kelley's in Brighton, salmon everywhere. Fine local beer everywhere.
Although we stayed at an RV park in West Yellowstone (Grizzly) because we were there in mid-October and needed hookups, I am told that there is good boondocking just west of West Yellowstone in the national forest. In Yellowstone, try the hike to Imperial Geyser -- nobody there but you and the bison.
In the Tetons, see if Atherton Creek Campground is still open when you get there, in the national forest just east of the Tetons. Very quiet, very well located, lots of wildlife. There is boondocking near Slide Lake, too. If you hike in Yellowstone or the Tetons, make a lot of noise -- September is the month when the grizzlies are eating like crazy to stock up for the winter, and they are not picky eaters.
If you are interested in more info on any of the places I mentioned, just plug those names into the search bar on my blog (see link below). Lots of photos.
