This would be a great time to apply the "mark-your-truck-as-a-waypoint" function on your GPS.
1. Turn GPS on and let it get a good GPS fix at your truck.
2. Mark that position as a waypoint.
3. Turn GPS off and put it in your pocket where you won't lose it (like you lost the fore-end of that expensive 28 ga shotgun).
4. Pull the GPS out and use as needed after you get turned around and lost chasing a grouse in the brush.

Edit: 20/20 hindsight being what it is, that was a really expensive grouse. These situations often start out with a hunter/hiker getting lost. It will cost more to replace the fore-end of that shotgun than to have bought a pretty decent hand-held GPS receiver.