Looks like a great trip, and it sounds like you've plenty of experience and know what you're doing.
If you're not set on panniers it's worth considering a BOB Yak trailer. I bought one years ago and have never looked back. For anything gnarlier than very light touring they're fab and handle much
better than panniers, esp off road, -the only thing that has em beat' is ruts. You can carry loads of stuff, which brings a whole bunch of new lightweight-but-bulky kit possibilities, and it's nice to just unclip them at the end of the day and have your light bike back again. Flip em upside down and they make a handy table too!
tips: other than the obvious tools/spares, take a bag of nuts and bolts and a roll of duct tape.
a water filter is really useful - I use a Katadyn Mini
eat nettles! ..a welcome addition of some greens to the diet of dehydrated crap, and they're packed with vit's and min's. The cooking liquid is a fantastic tonic