Please note that this is not a travel forum. It's about "backpacking" in the American sense, which is wilderness trekking. While many of us have traveled, much of our travel experience is not recent. I suggest you consult a budget travel forum, of which there are several. For one thing, I suspect you are underestimating what you can find "in country"--you don't have to take everything with you!

For what it's worth, you're taking far more clothing and gear than I did for traveling for three months at a time. I took one change of clothes (plus what I was wearing), including underwear, except two changes of socks. Everything was of quick drying fabric so I could rinse items out at night (often in the shower) and they'd easily be dry by morning even in damp weather. You might want to weigh what you intend to pack and see if you can even hoist it off the ground!