The course is an out-and-back circumnavigation of the Warm Springs Arm of Lake Sonoma. It is 86% single-track trail and 9% dirt fire roads, with the first 2.4 miles on pavement. The trail is relentlessly rolling with three significant climbs. There is about 10,500 feet of elevation gain and an equal amount of loss over the 50 miles. Trail quality is generally good; there are very few rocks and almost no roots. However, much of the trail is seldom used and so you can expect a lot of leaves and sticks on the trail. There are twelve creek crossings and it is likely that your feet will get wet in most – if not all – of them.