I remember driving around in that Blue area you mapped around. If you ever make this ride (or make it again) let me know.....I would try to make it up there.
That blue area is Joe Pool Lake. I have a GPS Garmin. The only way I know to program a whole route into it is to map out cross streets from Google etc, and input them as "via points" on the gPS. Its slow. If you know another way, let me know.
Here is a site for uploading routes to Garmin small devices, but does not apparently work with Garmin Nuvi Car/motorcycle style. http://connect.garmin.com/help/faq/devices