In answer to the recent inquiry: I can’t speak for other manufacturers, but Garmin’s Mapsource software has a setting for the road types along routes. I took my family on a camping trip a few weeks ago and we were on a single-lane dirt road for several miles between paved roads. We saw a group of wild turkeys cross the road and numerous deer bounding away as we passed.
Since this trip, I found the setting in Mapsource that the software uses to determine road types. Click the “Edit” menu and select “Preferences” and in the resulting dialog, select the “Routing” tab. There is a slider for “Road Selection” adjusting from “Prefer Highways” to “Prefer Minor Roads”.
I personally have the Garmin GPSMap 60CSx and wouldn’t trade it for anything else. I have had the unit just over a year and updated maps once from City Navigator North America 2008 to City Navigator North America NT 2009. NT is a smaller file-size allowing you to hold more maps on a single Micro SD card. I use a 2-gigabyte card and have both sets of City Navigator and Topo 2008 for a good portion of the Eastern Seaboard. Updated maps are imperative as roads are always changing, but Garmin does a good job of software releases and bug fixes. – Reid