Is the railroad track that goes through Dickson just west of the WAC still in use? It seems like that would be the perfect route for a light rail. Not only would it provide a great stop, lots of pedestrian trafic to Dickson, but it goes through Springdale, Lowell, and Rogers. I don't know how much it would take to convert it, or if that is even possible, but it appears to be the lowest costing choice. It also branches off in Rogers and goes right through the Wal-Mart HQ and on into Bentonville. Perhaps a stop at Washinton Regional, though it would have to break off just a bit. I am not too familiar with Springdale, Lowell, or Rogers so I don't know where those stops would be.
The biggest draw for the whole thing would be the ease with which to get to Dickson and with a little walking, football games (it goes by the Parking lot across from Baum as well). Just have parking near the stops up north and you don't have to drive down. It could also answer the question about moving the WAC as well as the parking deck for it.