Cheapest way to accomplish this goal would be a single lane busway like Charleson. Could have it connect 57th to 57th wrapping around the southern tree line of the course. Set up some fences or adjust the greens accordingly, but wouldn't need to sacrifice too much space. Add a transit priority signal on Cambie, as well as automated ticketing for anyone driving on the road. Or add an automated gate that raises and closes to prevent drivers from entering. Cyclists and pedestrians already have the Lanagara trail that would be mostly parallel to this. Problem solved
Edit: South Vancouver does have a East-West service gap, and running a route on 57th would help reduce crowding on the 49. Fantasy territory, but a route from Metrotown via 54th in Killarney > Sunset > Cambie > Kerrisdale/Dunbar along 57th makes sense imo.