RDS-TMC GPS Gadgets and Navigation Articles

I created a route for a trip that will take us through a few states. I have also loaded several POIs that we may want to check out as time and interest allows. Here is the question: If we start out on our route and then decide to check out a POI, how do I resume the interrupted route?

I just purchased a Garmin Nuvi 550 and have a question that I couldn't find and answer to at the Garmin website or in the owners manual:

When I create a route in Mapsource it doesn't give me the option of where to save it in the GPS. I want to save it to the SD card but it appears to only save it to the built in memory. Any suggestions?

Thanks!