Basecamp will not let you select map regions.
Basecamp requires Mapinstall in order to select map regions and you then are selecting in a tiny window with a deficient GUI.
Mapinstall will not send a mapset to a hard drive partition and requires some SD card to be plugged in to send the mapset to.
Basecamp has some nice features but takes two steps forward but also one step backwards at the same time.
Basecamp can't process Blue Charts and need another separate program called Homeport.
Mapsource is a nice all in one program so we don't have to install multiple programs.
To answer part of the OP's question:
When you install a map onto Mapsource, it creates a directory structure with XML, MDX, TRF files plus many other directories in the Garmin folder of your hard drive..
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