Deleted pointless trivia. Plus the Hexer that spawns outside of Johnny's is supposed to be the same Hexer, plus Clay can provide a replica if it's destroyed.
Well duh, but the highway that Johnny rides in while giving the truck driver the finger leads to Alqonquin. The streets that Niko walks in is clearly in Alqonquin. To avoid a wiki war, I'll do this.
Location of mission: Alderney