I am interested in using the Ardupilot for a ground vehicle application, and I need to enter a large number of waypoints for many different parts of the country. Saving and retrieving the waypoints is a must. I will also need to use an external EEPROM, but that is a different story. I wrote a waypoint editor that can help users manage a large number of files, and, also, save *.KML files for display on Google Earth. I will be very glad to share the editor with anybody, and, if enough people have interest, I'll post both the executable and the source here. It also allows you to create a track with the shape of a regular polygon. Here is a screen dump of a track at the Boulder , CO Model Airplane field on Google Earth.