In a GOOD backpack, like my Norrøna, a normal sized, fit guy can usually carry around 60kgs for 10km, and 45 for most of the day or perhaps 30km, In reasonably flat terrain. The limiting factor is the stability of you knees really, and general fatigue.
60kg is probably half of the meat on an average moose, sans bone.
Here in Norway, a lot of moose is shot. Most as Wingnut says, and the the ones that dont have 4WD borrow it, a few are carried out though.
Even so most moose hunting is in teams, 10 guys w/permit for 5-6 moose. Shot one at a time 10 guys on one moose is not so bad.
Coordinated posting, combined with a stalker/driver is also fairly effective hunting.
K
Norrøna Recon Pack Video of it