Self supported. I've ridden my current wheels hard this year and the rim surfaces are scored and the back rim is worn down.
Then I'd opt for something strong, easily repairable, and a little wider like the velocity a23 or the H Plus Son TB 14. There is always a trade-off between weight and durability, and I'd opt for something on the sturdy side of that trade-off (the H Plus Son weighs 490 grams, the velocity A23 450 grams). I'd run 28c tires as well.
Sounds like a great trip; will you be posting pics on BF to make us all a bit jealous?