I'm new to this but i very well know where places are around home and i have previously been working as a professional map maker.
Some of the GeoNames are off by several thousand meters. Before i start to put them in the right places i want to verify that there is nothing else wrong. Is there any other ways to add GeoNames except for the web GUI which could give misalignment? More than a few seems to be off with approximate the same distance and direction. Is it common that people misalign the locations?
I use Geosetter to geotag my photos. Geosetter use geonames.org for for the location data and i have noticed before that it sometimes gives very strange location data for the GPS coordinates.