Quarter it. Take the backstraps and tenderloins out first trip, ans if you can carry a front quarter good. Takes longer to bone the meat but if time allows then you won't be carrying extra weight.
Then pack out hinds, usually can only get 1 at a time. Finally if you want the hide and head take them last.
http://www.elk-hunting-tips.net/quartering-elk.html
http://elkhunter2.tripod.com/quartering.html
we use the gut less method or indian method of cleaning the animal remove hide and then quarter. remove backstraps, count back about 5 ribs or so cut into carcass and remove tenderloins by fingers.
I have packed a few out alone so it is possible, hard work, and rewarding. But it is more fun if you can get a hunting buddy to go with.