I've just been playing with similar questions for a week in the Alps. As for spares, take anything that is unique to your bike. I took a mech hanger, spd cleats and a bikes worth of pads. I assumed everything else would be availible locally.
As for tyres, often the best bet if you're thinking of getting new ones is see what people are using when you get out there. They'll be the best people to tell you what works. I was surprised in the Alps that it all seemed to be maxxis, I was expecting a lot more Michlin and Continental which suggests people seek out what works rather than just getting what's easy.
As for packing the bike, get a big box from the local bike shop and a spare. Reinforce the sides. I covered my entire box in parcel tape to make it shower proof and reinforced the bottom with duck tape just to help where they drag the boxes. Don't forget to remove the wheel skewer as this is the bit most likely to poke through the box. I took stem off, rotors off, rear mecjh off, pedals off, brake calipers off and front wheel off (brace the front wheel) and made it both ways unscathed (although the box took a battering).