Helemt – yes, why wouldn’t you, unless you intended to have a TJ induced rotational injury, I don’t buy his claim that it’s more likely than the “smashing rocks through skull” type injuries. I’m lucky though, my wierd shaped head fits Giro L/XL helmets perfectly, currently rocking an E2 which I barely notice despite my long flowing lucious locks mop top.
Bike – Anthem-X 29er? I do buy into the whole better rolling/more comfortble thing, and I’d not want slack angles over that kind of distance as I find them hard work manhalndling wide bars/short stem/slack forks on long rides. On a budget any of the 29er hardtaisl would probably do, I’d happily do it on my rigid swift.