In my opinion, a bearing to the truck is useless except in easy terrain. It's also useless if you don't know the exact location of the truck on the map. Even a couple hundred feet difference can make you think you are on the opposite side of a nearby trail.

Look at the example below. You are lost where the red flag is. A bearing to the truck would have you crossing almost impossible terrain. If you know how to plot a bearing and distance on the map, you would find you are very close to the trail. You don't need a protractor to do this. It's very simple to just use the compass.

This discussion has been helpful. Now I know it's useful to mark a waypoint at a known location. Then I can use that point as a navigational aid to determine my location. Brainteaser to follow.