Well, nobody here answered, so I continued to gnaw away at this problem (Fitting all of North America on my old c340. I won't bore you with the false starts (many), just the bottom line details:
1- The lower 2013 lower 49 still fits the C340 on-board 1 gig memory.
2- The rest of the north America (Canada, Alaska,Mexico and some South American little guys are all relegated to the 2 gig SD regardless of how you try to slice them.
3- The GarminAexpress.exe map downloader is only suited to direct-to-GPS downloads (it never did mount on my laptop). It does work to first receive the full North America subscription onto your PC hard drive (or aux drive with beaucoup memory).
4- Thereafter, you can readily use MapInstall.exe to mix and match a download. to GPS or SD card, your choice.
5- On the c340, you can list for view the contained maps, but the display content is obtuse. The first line is the version ("2013.30" in this case). The second line, item [1] lists the content of the built-in m1 gig memory. The third line, item [2] attempts to list the SD card content, and starts with the first item, then into runtogether and off the right side of the screen.... unknown....
6- To determine whether, for instance, I had Mexico, I went to the "State" selection and started "Chiua.., and it auto-filled "Chihuahua", so I know it has Mexico. Then "Ontar..." for Canada worked, too.
Just thought you all would like to know..........
Ange