I spent 4 months traveling through South America - and traveled light (one small backpack... 80% of it was camera gear, 10% was a bottle of wine, and the rest was for clothing.)
If you're interested, here's the blog I wrote on the way, so you can see my style of photography, and whether my recommendations are going to work for you: http://blog.travelpod.com/travel-blog/seankervin/1/tpod.html
I'll first tell you what I took... and then what I would take if I had to do it again.
Super wide: 10-22 (950)
Wide: 24mm 2.8 (450)
50mm short portrait (10)
85mm 1.8 long portrait (1300)
70-200 f/4 IS (1250)
The numbers in the () are the number of shots that I actually took with that lens. Back home, my favorite lens is the 50... but although I carried it for 4 months, I didn't really use it. The 85 was far more useful for capturing photos of people, and interesting things because I could be more discrete. That 85/1.8 really delivered.
I used the 10-22 a LOT... but it only delivered 2 photos that are wall worthy.
I hated the 24mm. It sounded like an electric razor... and although I loathed putting it on my camera, it had an exceptionally high wall rate... I have a love-hate relationship with all the photos this lens credits on my walls.
The 70-200 saw the most action, but realize that's the lens most likely to get motor-drived, but the important thing is that half of the shots had a 1.4x converter.
So, I recommend adding the awesome 85mm 1.8 and (sigh) the scratchy 24mm 2.8 to your kit.
Finally... consider a used 5D classic. I just bought one off Ebay for $750 and bought the 35L (on sale now) to replace my 24 - I LOVE it!