I began with the existing orienteering map. As I ran the trails this morning, I made notes about how to map them. If I understand the MTB O' mapping standards correctly, you draw trails based on width (> 1.5 meters or < 1.5 meters) and riding difficulty/speed. It seems straightforward. Single track trails are < 1.5 meters and the occasional double track is > 1.5 meters wide.
Judging the speed is a bit difficult for me because I'm a lousy bike handler. I tend to slow down more than a good mountain biker would.
The map I was working on today is the overlook area at Clinton Lake. The trails are generally nice, with a few rough and rocky areas. There are some hills. There are some paved trails and roads. I think it'll make a reasonable area for a local event.
My other MTB mapping project is the river trail area which is largely built on a trail network of one-way trails. After I wrote about mapping those trails, I got an email with a new symbol that works pretty well. Take a look below: