Thanks for the suggestions. I've got a good weight right now. I've got a Goruck 30lb played and also a homemade configurable plate made from 1/2" steel rods for 10-25 lb adders.
Sounds like external free is the way to go. The hiking oriented internal frame packs seem to lack robust mounting points. At least that was my impression of the hear at REI. I originally went to REI and left feeling like Kelty was the most "rugged" of my options. Some of the ultra light weight options felt like tissue paper.