I'm a fan of the external frame pack and recently decided to swap my Swedish LK35 for a ALICE pack, the pack in question was the large model and after buying a new set of shoulder straps (my old ones were missing??) I packed it and took off for a weekend in the woods.
Some basic info on the ALICE pack and US webbing in general can be found here - http://www.georgia-outfitters.com/_alice/alicemanual.htm
And a good article on packing your ALICE pack can be found here - http://www.ehow.com/how_6723696_load-alice-pack.html
Now i'm not sure of the capacity of the pack - some say its 70 litres others 50 litres - personally I'd be inclined to below 45 - 50 litres which is fine as thats easily enough for a weekends gear. These packs are designed for troops working in extreme winter conditions and as such are robustly made with some excellent features. The two lower left and right bottom external pockets are ideal for taking a 58 pattern waterbottle - while the middle and slightly larger pocket will take a set of German mess tins or my preference a set of british mess tins (with room for a few items stuffed around them) the three smaller top pockets appear to be designed for the addition of extra magazines of ammunition but are ideal for your possibles - mine contain, first aid kit, note book, sharpening stone, para cord, matches, fire steel, hi viz marker flag, mini parafin lantern, torch, whistle, light sticks, tinder etc - or if I'm carrying my jack flask with something hot inside it then that goes int he middle pouch for easy access during a lunch stop for example.
The lid has a small pocket ideal for mapps and such but I usually store my wash kit and housewife (sewing kit) in there as its a low bulk kit.
The main sack has a large inner pockets mounted high at the back and this is wear I store my rations and a 2 qrt canteen keeping the weight high on my back and shoulders - in the main sack I then packed my therma rest, polish army tent, down jacket and sleeping and bivi bag.
While appearing bulky the pack is surprisingly comfortable and stable on the back. The external frame has a comfortable hip belt and keeps the pack off the back 100% - in fact after a days carriage hiking through the forest the only two wet points where a small area across the shoulders and on the hips which is excellent as I hate a wet back after hiking and the horrible sensation of chilling as the cold wind dries the sweat dampened clothing ...................
I'm not a fan of the smaller medium sized ALICE pack but I am really pleased with the large one its a comfortable carry and fits my back perfectly so for bushcraft purposes I think this is a excellent pack which will be hard to beat and one I'm sure to use again and again in the future.