In Maemo Mapper, go to menu > maps > manage repos. Once there, the cache db field will show you exactly where the downloaded maps are.

Create a directory to move the maps to (like /media/mmc2/maps ) and move/copy them over. Then just change the cache db field in Maemo Mapper to the new location (I think you'll have to do this once for each map service )

As for the sample files, you should be able to delete them via the File Manager. There's also a tutorial app that can be uninstalled via the app manager.