Assuming you actually mean skiing the backcountry (away from the resorts) and not just a way for kids to call the back bowls at Vail something it isn't.... I'll inject some knowledge....
First, before you kill yourself or someone else, please buy AND wear all the appropriate gear (beacon, shovel, probe, 1st aid kit, etc.) and take an avy 1 class. Depending on where you live, there should be free classes available.
As for skis, you don't want anything too long since you'll be skiing trees more than you think and less big open terrain. At your height/weight, I would be looking at something around 186-190 fully rockered, or something 184-188 with a flat tail and tip rocker.
Regarding camber, it's skier-dependent. Personally, I prefer a slight amount of camber underfoot since you won't always be skiing powder and will sometimes find yourself skiing shitty conditions.
You'll want the flex to be middle of the road. Too stiff and you won't have any fun in deeper snow. Too soft, and you'll legs will feel like nails driving into them when conditions aren't ideal.
And as for ideal shape, something 110-120mm underfoot. Anything wider, and it's just unnecessary weight (you have to take that into consideration). Anything skinnier, and well... you may as well be at a resort.