OK - I now know the the process. Here it is:
From web-based topographic server (MnTopo in my case), zoom in to subject area, download "Contours" (not DEM).
Zipped file e-mailed to you containing shapeless. Open in ArcGIS and back save to AutoCAD 2010 or earlier.
Open file in Auto CAD, create bounding box, and clean up stray contours. Save as a .dwg .
Open .dwg in SU and save as .skp
et voila!
Cheers, Jeff