Here is a course I measured in 1988. It is the only cycling course I ever did, and I had to make up what I thought was a reasonable route. I described it as:
Measurement Method - The three mile course was measured as though the runners had full use of the entire road.
The 14.91 mile bike course was measured staying about 3 feet from the right hand side of the road. About 100 yards from each corner, the measurement took the shortest route around the corner, then gradually drifted right for about 100 yards until once again 3 feet from the edge.
The course map is shown below.