There is a theory that the stronger your core stabilizers (erector spinae, transverse abdominals, and obliques) the less load your discs have to bear since they provide more support, think of these muscles as your chassis, this doesn't mean do a million crunches, more like a variety of planks with PERFECT form keeping your core tight and strong and as soon as you loose an inch of your technique you stop, wait and do it again. I also recommend deadlifting with very light weight, with PERFECT form, going slow and aiming for 20 - 30 reps. This too will significantly improve core strength without overloading the discs / vertebrae. As far as out smarting your back, the very best thing to is to have pack goats, llamas, horses ect OR bring a young hunter who will carry all of your stuff, and in exchange he gets to learn about your best hunting spots / knowledge (give him some meat too). As far as gear, obviously go light as possible but also have a pack that has an awesome hip belt that takes the load well.
Hope this helps
Hope this helps