I know you're debating between the two sizes of MBPs, and if it's going to be your only computer, get the 15" for traveling.
However, I agree with others that really the way to go is a Macbook.
I travel to India with a refurbished Macbook and leave my MBP at home. The Macbook has been for me the most practical and carefree device for communication, writing, entertainment and photo management.
You have an awesome trip lined up. Best of luck to you.