Bill, could you provide sample addresses, or intersections? Routing from town to town generates what appears to me a sensible route, as shown on the picture above.
Glenn, going to Strathroy would indeed not make sense. That would be travelling the complete opposite direction for about 40 kilometers, or more. This might have been fixed since Streets & Trips 2007.
Just for the record, I'm using Microsoft MapPoint 2009 (and also Microsoft Streets & Trips 2008) at this moment. The trial 2009 version of S&T expired a couple of days ago on my mobile laptop. I could test it again on S&T 2009 later tonight when I get home, but I suspect I may get the same result.