I figured out how to do this but then forgot by the time I wanted to do it again. So I figured out a different way to do this and this time I wrote it down. Here it is:
How to use Paths from Google Earth to create a map (img file) that can be loaded into a Garmin etrex 20. This is if you have too many tracks to be loaded at once for your etrex.
1. In Google Earth save folders containing paths into .kml files. If you want the colors to come thru, save different colors in different folders.
2. Convert the .kml files you created into .gpx files. I use KML2GPX.exe.
3. Use IMGfromGPX to create a single img file from the gpx files. Here is where you add the color back in. This creates gmapsupp.img.
4. Use JaVaWa Device Manager to install gmapsupp.img. gmapsupp.img onto your etrex 20. Push the install button. Locate button on JaVaWa Device Manager. When the dialog comes up, locate the file gmapsupp.img. gmapsupp.img on your computer. When asked if you want to Overwrite click No. It will still install gmapsupp.img but will rename it to gmapsupp1.img.
5. Later if you change something in Google Earth, go into JaVaWa Device Manager and remove the gmapsupp1.img and redo everything starting at number 1 above.
6. Probably want to donate something to JaVaWa. (No I'm not affiliated with them).
This >appears< to work. If anyone knows of any potential problems with this way of doing it, please post it here. Thanks!