On a road trip last year we learned that the combined height of a
canoe/kayak plus our vanagon (especially w/ a poptop) can impact the fees
that we paid to take our van on most of the ferries up in the Puget Sound.
The ferryman brought out a long measuring stick, held it up to the van,
eyeballed it, and ticked a box on the form next to the word EXPENSIVE!!!
All said, it was definitely worth it.  We had a blast.

Brent
www.weidefamily.net/vanagon/