OP-

I may be full of crap, but:

I don't think that will be possible with the type of example you gave. The scale or distortions for clarity will most likely not lend themselves to the maps that you can use on your device.

I would suggest trying Google's application 'My Tracks', which will chart your ride by GPS and will overlay your route directly on Google Maps. Of course this means that you will need a decent connection to the GPS sattelite. My Tracks will work continuously, or I think you can stop periodically and note waypoints.

I guess what it comes down to is that the given trail map needs to be based on the same data set as your GPS; well, in many cases that common base is gonna be Google Maps. I know Google is kinda the big juggernaught, but it is very widely used.

Sorry, I don't have a lot of experience with My Tracks, I've only used it on some road rides and hikes. But it does seem to overlay your route quite nicely over Google Maps. The application also does the usual cyclometer stuff as well as elevation data.

As far as I know, My Tracks is in beta. I think there are options for sharing and consolidating with other users' data.

And, I'll just finish off by saying that I have not used any Garmin system stuff for this. Perhaps someone here will chime in.