My best advice is to make sure that the pack you buy, either has a detachable day pack, or the space to store a day pack. When traveling for that long, you are going to want to secure your pack in your room, but also have an option for day trips and touring. I own an eagle creek pack that has a detachable day pack. Best thing I ever purchased as a traveler. I unzip the daypack and cruise out the door with everything I need, except the HEAVY pack. Have a good adventure!!!
When an adventure ends you can never go back, never relive it, never hope to feel the same emotion. The secret is to not try and go back but to keep searching for new adventure....