Yes, look for the detail menu in the settings. However, setting it to auto is normally what you would want. Also look at what profile you are using, have not used an Oregon 600 but IIRC the one you want is something like "recreational".
Are you sure you have the map enabled in the settings? Hard to understand what you are seeing, but if you don't have the map enabled you might just be seeing the basemap, which has almost no detail.
Do Basecamp and Mapsource show the map(s) correctly?