Christof Teuscher posted the route:
Mark O. Hatfield Memorial Trail in the Columbia River Gorge. More info about the trail can be found here:
According to the pages above, the trail is 60mi long and has a total elevation gain of 13,500ft. However, my Ambit2 logged 55.3mi and 16,566ft of EG. Note that it died about 1mi before the Starvation Creek TH. So my final mileage estimate is about 56.3mi.