I was wondering how to use that tool and just in case the OP is also, here is my first contribution toward answering a question someone else has posted... I've been pretty good at asking questions and getting lots of great answers! Payback time... I hope
Use the tool M.Tyler points out and SELECT the Span/Contour Properites mode
I wasn't sure how to screen shot the little cursor but it will change to an ARROR wih the SPAN indicator ~ . Place the cursor on a section of your line you need to measure and click. The results show are:
TYPE - it will tell you what type of section you clicked on.. i.e. LINE or BEZIER
LENGTH: this will tell you the length of that SPAN section you clicked on.. basically node to node
< THIS IS THE PART YOU PROBABLY WANT TO KNOW >
VECTOR : will report the total length of all the spans that form a complete vector length. It will tell you the type of vector ( open / closed ) the Perimeter ( in the case of an open vector this looks to be the TOTAL LENGTH which is what you are looking for ) and it will tell you how many spans are joined up to create the total vector length.
Boy I hope I got this correct ... please someone let me know if I didn't and I'll edit or delete so it's not left up here. I had to go in and figure this out so if I did get it right, then I learned something also.