Investing in a good-quality backpack is extremely important, not only for your back but also for your stability. Luckily, there are countless options, so quality doesn't have to come at such a significant price tag. However, be sure to choose a backpack that is right for you.
I would highly recommend going to a sports store and properly getting fitted. Not only can the staff answer any questions you might have, but they can also teach you how to properly pack your bag. I never thought there was a right way to pack, but believe me, packing properly makes all of the difference!
And don't forget boots! Finding the right hiking boots is just as important. Yes, this can be another pricey item, but trust me, the investment is worth it. With proper boots, your feet will have the support they need to keep you balanced. Remember, you will be hiking at least 26 miles, so you will want a boot that is comfortable.