The Yahoo is an annual event in December. It is an event where you estimate your time at the beginning, and run the route to see how close you get to that. Runners are set off in reverse order based on estimated time, with the idea being that all runners converge on the finish at roughly the same time.
This is a link to the Yahoo course map. If you click on the link, you can zoom into the map. It also has pointers and instructions about key areas on the course. If you select the ‘OpenStreetmap’ option from the list option in the top right-hand corner of the map, you can find the exact road names.