If your bike is well-maintained and you are on top of the maintenance (for example, could you tell me now, without checking, how worn the chain, tyres and brakes are?) you don't need to carry anything other than puncture repair kit, a couple of inner tubes, chain lube, a small multi-tool for minor repairs, plus any of those wear items, which you estimate are going to wear out during the trip. If they are commonly available you don't even need to carry them as you can just buy them and fit them as needed.
If all this is meaningless to you, you'd better be prepared for some breakdowns along the way and carry cash and a credit card to pay shop mechanics.