If you use GeoGet, this task is pretty simple:
Although the database of a:Drake is the same as the database of GeoGet, it's not recommend to overwrite the original database from the GeoGet by database of a:Drake!
a:Drake can directly import GPX (standard GPX by Groundspeak, no extra extensions). Import is suposed for quick load of new caches, massive load of data should be done via GeoGet.