The GPSMapEdit/cGPSMapper/MapSetToolKit is the best solution. It's a bit more effort but the final result is a IMG map (just like Garmin's) that will upload to your GPS in high detail and give you total control over how the tracks, roads, lakes etc. look. It's no accident that the my tracks are bright green with black borders... it's easy to see on the Oregon. I have seven local riding areas I have combined into one map. This solution is also being used by riders to produce maps with hundreds of trails on them at no cost to the rest of us. Switchbacks Website: http://www.switchbacks.com/gpsmaps.aspx
I used the NW Trails to ride an area I was not familiar with last week and it was dead on.
Here's another example of a map I produced (shown in BaseCamp) where it's MY option as whether to show trail details as primary (solid lines) or secondary (dotted lines). The service roads are in yellow and in the north there is paved road shown in gray and black. At anytime, I can go back and edit anyone of these trails to improve either there accuracy or appearance. You do not have that option with overlays. I also included an actual picture of this map on my GPS with Garmins 24K Topo showing through in the background.
My suggestion is to start with a single track and go through the process of creating a map. Once you know how, it opens up a lot of options, plus it's actually fun to do this.
You just need to get your data into a GPX format. From there, GPSMapEdit knows how to handle it. I attached a small zip file to this message that contains a very simple map (startupmap.mp) that has all the settings I use in GPSMapEdit to create the Garmin IMG file. It's a good template to start with, you just need to "add" your gpx tracks to it without having to figure out all the "Map Property" settings. The *.mp file (that GPSMapEdit produces) is just a text file. You can open it with Notepad to view the contents, or download GPSMapEdit to view it in the application.
These videos are kind of hard to watch but they detail the steps (links to the free software can be found in my above post). Ignore the part where he uses the DOS window to compile the file. You can set the path to cGPSMapper in GPSMapEdit and it will compile it from within the application.