Have you noticed that Philip K. Dick fans tend to be Robert Anton Wilson fans, and vice versa? Probably you have. Before I discovered Illuminatus! in college in the 1970s, I read and enjoyed Dick (i.e., I read him before he was "cool."
Ted Hand, the hard-working Philip K. Dick scholar, has a long blog post about the two writers that seems to collect and link to much of what RAW wrote about PKD.