In "Fahrenheit 451" why did Faber decide to go to St. Louis?
At the end of the novel, Montag is on the run from the mechanical hound, and he goes to Faber's house. It is only a matter of time before the hound, and the authorities, find them both there. They realize this, and so devise an escape plan. Montag will try to throw them off the scent by dressing in Faber's clothes, and Faber himself will take off, leaving town. Faber himself will probably be captured by the authorities for being an associate of Montag's, so he needs to get out of there two.
Faber picks St. Louis because he needs to leave town and must have a destination. Secondly, he tells Montag that he wants to "see a retired printer there." Faber wants to continue their insidious plan of planting books in firemen's houses, and he needs a printing press in order to start making those books. He also wants to start printing books just to have books around again, and to start distributing them to be read. He says of this move that he's "getting out in the open myself, at last." He has felt for years that he's been a coward by not fighting back, by doing what the government told him to do. Montag has inspired him, and so he decides to continue his rebellion in St. Louis where he has access to a printing press.
I hope that helped; good luck!
Before Montag flees the city, he stops at Faber's home to inquire about what would be the safest route to escape the city. Faber responds by telling Montag that he should head towards the river and follow the old railroad tracks, where there is a good possibility that he will run into a group of hobo intellectuals that will help him. Faber also explains to Montag that the government doesn't consider the homeless intellectuals a threat and leaves them alone to wander in the wilderness. Faber then tells Montag that he will be leaving on a 5 a.m. bus to St. Louis, where he will meet up with a retired printer. Faber finally plans on taking action against the government by using the money Montag gave him to begin printing copies of invaluable works of literature. Faber senses that the dystopian society will collapse and wishes to partake in rebuilding a literate society in the future.