My understanding is that your journey will be a series of trip segments saved in current.gpx.
While there is a limitation on nüvi units to the length of a trip log displayed, there is not to my knowledge a restriction on the size of trip logs.
My understanding is that you will be able to convert the trip log saved into .kml or other formats for display in other environments.
Using the POI tools you can clean this up so it only contains your progression along the journey.