I use a Garmin 705 on our tandem and have been trying to deal with Mapsource quirks for quite some time. I've tried Mapmyride and bikeroute toaster, but haven't found them very friendly. Somehow I stumbled on to Ridewithgps.com and it looks pretty promising. The routing is very fast, bike trails are supported and I can store direction in a Garmin-friendly format, either routes or tracks. The climbing figues appear more realistic than I've gotten out of other applications. Anyway, it's free, no ads and worth a try if you're dissatisfied with whatever you're using.