After you have found and marked where you are on the map, you can save a waypoint at the current location. Make a note of the waypoint ID number or name. It's surprising what one can forget.
If necessary, you can now 'project' this waypoint to the place you want to go. Alternatively, you can just project the known waypoint (say the car) to where you want to go, say a pass, above or below a cliff, or some other geologic feature important to the route. Draw a bearing line on the map from your current location to where you want to generate new waypoint. Place the hole in the center of the compass rose over your current location, align the grid with true north and note the bearing. Now use the scale to measure off the range. Making sure that you start from the GPS waypoint that corresponds to your current location, enter the range and bearing into the 'project waypoint' dialog, and be sure to record the name of that new projected waypoint you just created. Now you can navigate to or around this waypoint safely.
One advantage of carrying this tool is that if you have chosen not to record GPS waypoints during your trip, you can still use the GPS to navigate provided you have uploaded one or more waypoints that are clearly represented on the topo map. Topographic software now makes this very easy to do, and it's a comforting feeling to carry a GPS with this data when you are not completely familiar with an area.
Thanks to Maptools.com for kind permission to use their compass rose as a start for the graphic.
No commercial use of this tool without permission.