Jeffrey Combs, who plays Kevin Burkoff in 4400, gives Tess a book while they're in the mental institution by H.P. Lovecraft. In the movie Necronomicon: Book of Dead (1993), he plays H.P. Lovecraft.
This long episode is sometimes split into two when aired by a TV company.
Besides playing H.P. Lovecraft as stated above, Jeffrey Combs has starred in several films based on Lovecraft's work, namely Re-Animator (1985) and its sequels.
Both actors Hiro Kanagawa and Kavan Smith had acting roles in the science-fiction show Sanctuary (2008).
Shawn and Kyle meet at Robson Square in Vancouver, BC coherently, for the first time since the happening. As they stroll and catch-up, the sculpture, 'Primary no. 9' by Michael Banwell, is in the background (at around 19:30)