While doing some route planning I came across this handy tool which converted a Google Map route to a GPX file.
The main reason for doing this is to generate a Caches-along-a-route PQ.
ie you can plan you trip using google maps and then generate a GPX file which you can plug into the PQ site..
Note the tool is essentially a bit of script which you use on your toolbar to execute on Google maps page .. easy as..
http://www.elsewhere.org/journal/gmaptogpx/
Note with a bit of editing of the GPX you can also generate a GSAK CSV filter too.