Garmin Mapsource TOPO 2008 for nuvi 350?

TOPO offers topography maps for GPS unit.

It is useful if you frequently travel/hike in off-road areas. The road data is typically not very accurate and the US topo maps are not routable.

From Garmin's website:

Features include:

* Digital topographic maps, comparable to 1:100,000 scale USGS maps
* Terrain contours, topo elevations
* Summit locations with elevation
* Trails and rural roads; city neighborhood roads
* Interstates & major highways
* National, state, local parks, forests, and wilderness areas
* Coastline, lake and river shoreline; wetlands; perennial and seasonal streams
* Searchable database of cities, geographic names, summits, lakes and more
* Elevation profile on PC and compatible units; estimate terrain difficulty
* Allows you to plan your next outdoor adventure on your PC and download routes, waypoints and map detail to your compatible Garmin GPS
* Includes lakes, reservoirs, waterways, rivers and streams with icons to represent boat ramps, dams, campgrounds and trails

Here's a link with some previews of the actual maps...
http://www8.garmin.com/cartography/mapSource/topous.jsp

I have Topo 2008 on my Nuvi 350. It works well EXCEPT the map is not routable. They are hiking maps. There is a trick:
1) enable your NT map
2) pick a route
3) switch to the Topo map
The Nuvi will route showing the Topo map, but using the NT roads. So you may be on an NT road that does not exist on the Topo map.

Note: If the Nuvi recalculates, you will need to go back to step 1.

Click below for a few nuvi 660 screen shots with topo 2008.

http://www.catalina42.org/photos/nuvi660topo.jpg