After Googling 'Apache trailing slash problem' for several days and trying various suggested solutions, the one fix that worked for me was altering the 'UseCanonicalName' to 'off' . Why this worked, I have not idea...but now I can leave off the trailing '/' and the server will look for an index.html file and not an extensionless filename.
p.s. - I was blown away at just how many hits I received on the Apache trailing slash search.
Russ