Your map link didn't work for me.
Do you mean this :
http://goo.gl/maps/CQ5WQ
I haven't driven that road for a while, but I suspect there is about 5km of gravel through there between Waingaro and SH23. (Streetview seems to disagree, perhaps I'm thinking of somewhere else). If you're allergic to gravel you might want to Streetview the route from SH23 backwards.
Either way, the route looks good to me.
I'll plan to meet you where ever you hit SH23.
Which appears to be at the intersection of SH23 and Ohautira Rd (about 8km out of Raglan).
Can someone please confirm and if there is any change in route please keep me informed (021 742 634)* so I'm not left somewhere in the dark :-)
I dropped an email to Trevor as well. He will be an interesting character to meet.
* remember there is probably no cell phone coverage along many sections as you get closer to Raglan