Unfortunately you will not be able to transfer tracklogs for Garmin nuvi (the exception of some multi-modes rare as the nuvi 550). To my knowledge, there is only one solution: turn the tracklog (gpx, kml ..) in vector img garmin. This file is interpreted as a map and read normally by nuvi when placed in the unit's Map folder. Certainly have to be enabled in the configuration of GPS.
There are several programs that save gpx on img. A simple and practical is the gpx2img.