Instead of taking the factory wall plug to charge my phone, I have purchase a few dual port chargers... including one rated to charge my tablet and my phone... it even has retractable prongs... and I make sure I have enough wall adapters to plug them into as well. My daughter even takes an extension cord to make sure she can charge all of her devices even if there aren't enough wall outlets.
Don't forget to have travel battery packs for your phone, and make sure you have enough cords and adapters to keep them up, as well. By a small see through bag to pack them into, and pack it on top of your clothes for easy access.