"Perhaps if one was really worried you could put your down gear in the trash compactor bag, then put that in a nylafume with everything else you want to keep dry?"
I tried a pack of three (from Sears) several years ago. I went through one per trip, and, really didn't care too much for packing food with my sleeping bag, anyway. I was also using it as a Bear Bag, which was nice because it rains many nights. The last trip I slipped on some muddy rocks (coming down one of the peaks) and landed on my butt/bottom of the pack. The pack was fine but the food bag had split the liner, as I found out later. I got my overall weight down to about 5 pounds for the NCT. Since retirement, my usual trips are a week or two and much prefer more reliable gear rather than SUL stuff, so, it has crept up to 8-11 pounds, again.
I find reliability, durability, and low volume mean more than lightest weight because of the number of days I am out.
Anyyway, I am thinking that July might be good for doing the Long Trail. But, I think I will need more pack than the Murmur. Mostly food, I believe.