The maximum time to complete the ride appears to be 15:45, which is fairly reasonable, depending on your skill level and ability to find a pace line at your speed.
According to the elevation plot, the course has over 9000 ft of climbing. Although it's not extreme, I wouldn't call it flat.
Have you checked out the DC Randonneurs? A 300K is pretty close to 200 miles and can be stretched into one by riding a few bonus miles at the finish. The minimum average speed is only about 9.5 mph (including stops).