What is the setting of Mr. Murder by Dean Koontz?

Mr. Murder begins at the Stillwater residence in Mission Viejo, California, where Marty and Paige live with their two daughters. At the same time, Alfie is fulfilling another contract for the Network in Kansas City, Missouri. Alfie fulfills his mission there, but afterward is drawn by a nameless force to leave his usual routine. He packs his bag and instead of heading for the airport as he is programmed to do, he begins driving toward California. He isn't missed at first, but it soon becomes obvious to his handlers in New York that he has gone off the rails. In Topeka, he changes vehicles, and then continues westward and heads to Wichita. From there, he makes his way to Oklahoma City, filling his tank and leaving his suitcases behind in case he is being tracked. East of the Texas border, Alfie pulls into a rest area where he again makes changes to avoid detection. He finds a man who is his basic size, and after killing him, Alfie takes clothing and shoes from him, leaving the final transmitter in his shoes behind in their Road King. Without sleep, he continues through Flagstaff and finally on to Barstow, California.

When Alfie finds his way to Mission Viejo and crosses paths with Marty for the first time, he forces them to flee their home and head for the only place they feel safe. After spending a night in a motel, they drive to the Stillwater family cabin outside of Mammoth Falls. Alfie follows them there and their final confrontation happens in the abandoned church called the Prophetic Church of the Rapture. Followed by agents of the Network, the Stillwater family is finally rescued after Alfie is killed. Karl Clocker follows Alfie's example and goes off the rails, turning on his Network partner Drew Oslett and rescuing Marty and his family. He takes them from Mammoth Falls to a safe house he has created in Jackson Hole, Wyoming where the Stillwater family becomes the Gault family and begins life again.