Geomapping with Reilly

 refers to an unmarked and repeatable quest in Fallout 3.

After completing the quest Reilly's Rangers and offering Reilly your help with their mapping service, she will give you a Geomapper Module. As long as you have the module in your inventory, it will record every new location you discover, for which Reilly will pay you 30 caps per location every time you return to the Ranger Compound and talk to her. Don't forget to speak to her right away, after receiving the module. She will pay you for the locations which you already have on your map.

Bugs

 * After getting the Geomapper Module from Reilly, sometimes all your notes up to date will disappear. To get rid of this bug and restore your notes, simply save and reload your game.  All notes will be restored.
 * Another possible bug is that you won't get paid for locations you already have the first time you talk to Reilly after she gives you the Geomapper Module. She will say that the Rangers already know about all of the locations you have and will give you nothing. If this happens, try immediately talking to her again. If she still won't pay you for the locations you have already discovered, try leaving the Ranger Compound and re-entering before speaking to her again.
 * Sometimes, if you talk to Reilly and ask for the caps for the geomapping, she will say that she will give you the caps, but will make her way to her bed to sleep. When you wake her up, she will say that she already has all those locations and will not pay you.
 * If you have the Explorer perk, you can talk to Reilly immediately after, and get money for all the locations, even if you haven't been to them. You get around 2000 caps for all of them, if I remember correctly.

NOTE I got 2154 caps having explored about quarter of the locations so it may be possible that you get more for actually going there or there is a caps limit to what she pays you.

Special Items

 * Geomapper Module