Why not just filter as you go from the portal? Plenty of streams on the way to Trail Camp.
That's what I did - dirty bag bladder - Sawyer Mini - to Nalgene bottle - steripen to top it off.
Doesn't take more than 5mins each stop once you get the hang of it.
I just carried 1 litre at a time. Saves about 2-4kg of water weight on the way up to Trail Camp.
