As a fan of GTA V I would have to say, none that I know of.
Anyone producing such a route would have to tread very carefully with regard to copyright issues which is why we probably haven't seen anything along those lines. Essentially it wouldn't be too hard to do - you could take the DEM from any island with a mountainous interior roughly 6 x 9 miles and impose the map on that. However where you would come unstuck is the work needed to emulate what several graphics artists spent several months if not years on, essentially recreating a microcosm of LA and the surrounding area.
It's been a long time since I played GTA V but I do recall a number of mods which actually allowed you to drive the freight train and the transit cars.
