The "Trench" from Watson Lake, Yukon, to Prince George, BC

Follow the blule diamonds on the VFR route from Watson Lake to Prince George, a total distance of roughly 500+ miles.  While the Trench itself is said to be roughly 320 miles, the distance between fuel locations (Watson Lake and McKenzie) is about 440 miles.  The highest point in the route is 3500 feet and is in a narrow valley, so when the weather is bad here you can only turn around and go back, probably all the way to Watson Lake or McKenzie to re-fuel and try again.
Distance between each diamond symbol on the VFR route is approximately 4 miles
Highest Elevation Along the Route  - 3500 MSL

Distance to Watson Lake - approx 195 miles
Distance to McKenzie - approx 220 miles