12 months is heaps for just about any route. We rode from Dublin to Vladivostok in 5 or so month. The route is on my blog in my signature. More applicable to SA the route below took us about 3 months along just about all the common highlights . I have to say that we manage to get bored sitting still in 5 min flat, so we don't tend to have many breaks of riding. I underestimated the distance (about 18k km on our trip) because the roads aren't as straight as other continents such as across Asia or Africa. So doing a measuring check on google earth is misleading.



Budget is a real difficult to advice on. There has been a recent thread with a similar question and my sums ended up getting flamed even though in my view you can't really argue the maths.
Anyway, the conclusion was that is very much depends on what lifestyle you want when you travel. You can't avoid paying for fuel or tyres which you can calculate providing you estimate the rough distance accurately (which I didn't). Same for typical transport costs. From Australia is costs a mint to get to South America. And it's 2 way as well. Then is depends if you want to camp or stay in motels. In Arg and Chile prices for that and food are equivalent to Australia. Further north it gets cheaper as you would expect. Then you have the food costs. You can cook pasta meals every day and live cheap, or enjoy the local food which you can do in or out of restaurants. Same applies as with accommodation on local costs. The 'menu del dias' in Peru was a nice welcome on our trip. But in large tourist centres such as Cusco you're back to western prices unless again you cook or eat in stalls.

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Tacos Tyring Travels.com