I've taken my Civic up a lot of forest roads in the area, and that would be similar to a Prius. Since my wife got an Outback, we usually take that instead, but out of convenience, rather than necessity.

I have not tried the road to the Pilchuck trailhead. There are only two forest roads we've done in the Outback bad enough that I might consider turning back if I tried them in my Civic: the roads to Ashland Lakes (FS 4020) and the road to Evergreen Mountain Lookout (FS 6550).

I actually think I could do both in a Civic. It would just be slow going to pick lines around and through all the giant holes and erosion ruts.