For a light set-up -- I'd either take my d5100 and the 18-200mm VR II or if traveling really light I'd just grab my P&S CoolPix S9100.
If I could grab 2 lenses and my DSLR I'd take the 18-200mm and the 70-300mm.
If I could sneak in one more lens I'd add the FishEye.
If everything goes right I'm off to Peru for a week in Spring. I'll bring all 3 lenses plus the CoolPix. Hate to get there and wish I brought that extra 2 pounds to have the right lens. I'll probably only have one chance to go ever....
And what will I mainly be shooting while there
B&W Street Portraits Peruvian Style of course
I must add I always travel light with carry on baggage only - no matter if I go for 2 days or for 2 weeks.