If Im using an microSD card how can better manage maps on my Garmin Oregon?
You can use the same technique described in M17 however there is no need to rename the first map set. Instead transfer the home map set to your Oregon, this will cause it to be loaded into internal memory in [drive]:\Garmin\gmapsupp.img. The travel map set can be transferred to the SD card in Mapsource where it will be saved as [SD drive]:\Garmin\gmapsupp.img. Replacing the SD map set when you travel will achieve the same results as described in M17.