Explorer I
I loaded the KML into Google Earth and saw only the waypoints as well. Tried exporting some of the routes from onX as KML files and got the same thing (just waypoints) in Google Earth. If you open the GPX into Google Earth and select "Create KML LineStrings" you will get something that approximates the route(s) but is very unwieldy as the routes are turned into separate waypoints and it slows Google Earth to a crawl. Its been a while since I dug into the KML format so I am at a loss for how to help you. Other than the GPX seems to work fine for me in onX/Gaia. I'm not familiar with the Magellan TRX so don't have anything to offer - maybe an internet search will yield something.That one didn't seem to work I can only see the stops.