I teach Leave No Trace Outdoor Ethics (and yes there are adaptations for fishing) and backpacking. Take a look at GoLite packs. They are frameless and extremely light weight. I carry a Jam, Pinnical, or Gust depending on how many days, distance, and season. I have a small fly fishing pack that stuffs right in. Waders and boots strap on the outside. Lightweight or ultra-lightweight backpacking requires some forethought, especially about equipment.