Replying to Ski Length?

I am 5'8.5", so 174 cm, and am looking to buy new skis. I'm 120-125 lbs. I will probably go to western next year and be skiing at Mt. Baker. I have a pair of 169 reno rockers 2011 that are pretty beat up and buttered out, so I am looking to get a pair of skis that can handle backcountry/gnarlier terrain but still do well everywhere else on the mountain including park. I was thinking 100 mm range, such as the blends or Jmos and was wondering what length would be best? Also I am game for other suggestions on width or ski. Thanks!