With these few tips, you'll make the job of packing up a string of horses much simpler, and your outfitter will love you for it.
Most outfitters have a weight restriction on gear, and oftentimes they ask for no more than 60 pounds of gear plus the rifle. Have your gear in a single soft duffel bag that's pre-weighed to their requirement. Or, if you have two duffel bags, make sure each weighs the same amount to ensure you don't exceed your outfitter's limitation. This makes balancing the load on a horse much simpler, and the soft duffel bags will fit well into a panyard or make a suitable top pack.
Sea To Summit makes very affordable, lightweight bags that are designed to keep your gear dry. You can pick these up in various sizes, and some even have compression straps enabling you to compress the size of your contents, saving valuable space. These bags are especially helpful when packing up bulky clothing; a dry compression sack will keep everything dry while minimizing the volume of space they take up. Try storing your electronics in them as well, wrapping them in a light towel to help absorb any moisture that might get on them while exposed to the air.
When packing with horses, not only is weight critical, but the volume of space that your gear consumes also becomes critical. Having a giant sleeping bag folded up into a garbage bag is not acceptable. Not only will the bag tear, potentially causing your sleeping bag to get wet, but the bulky size makes packing it on a horse difficult. Make the investment in a cold-rating appropriate bag that's also lightweight and efficient in use of space. Also, store your sleeping bag in a dry compression sack, ensuring that it stays dry and reduces the amount of volume that it takes up in a pack.
Handheld flashlights are fine for around camp, but if you find yourself hiking back to camp in the dark, a headlamp allows you to keep your hands free to balance along steep mountainsides or muddy, slippery trails while packing a rifle. A bright LED light with an adjustable beam is best.
In my opinion, nothing is more important than good boots. Having hunt-appropriate boots is critical. Ask your outfitter for a recommendation before you purchase new boots. Oftentimes it also becomes critical to pack along a high-quality rubber boot in areas that can get significant rain that might build up along the trail. At the end of a long day's hunt, there is nothing more relaxing than taking off your boots and changing your socks. I bring along a pair of socks that I designate for sleeping, and a lightweight pair of crocs that I can slip on and wear around camp. Go prepared, but go light.