here's the map of the routes of the automated tours that are running at SL8B.
the pic is taken from Daniel Voyager's blog, and he says the complete circuit of each half takes about 30 minutes - feel free to hop on and off.
i'm gratified to see that not only does the route pass by the exhibit of the Space Elevator at Bowness Island, but it also passes along two of the exhibit's four sides (ie, it makes a right-angled turn at one of the corners of the exhibit) :-)