Miele Cicli with Ambrosio 19 rims.

Is it an 80's road bike that can't take tires larger than 28mm? If you're a light person it's doable but a road bike isn't ideal for for a "massive tour". A road bike is good for going fast but once you put a pair of panniers on there you aren't going fast.

Without more details on the bike it's not possible to say if the bike is up to it. If you're seriously out of there in six weeks I'd take the bike to a shop and get their $.02.