Linsey, you mentioned the Injinji socks and they're pretty cool...I've found, however, with sufficient powder I get the same reduced friction benefits. I have a claw toe on each foot, so ensuring mah li'l toesies don't step on one another is a key blister prevention method. After giving them a spin, I gave up on Injinji's because, due to lack of padding, I'd get heel blisters even in my most comfy trailrunners, which I never got with more padded socks.
In your case, though, sounds like Injinji's and outer socks are a good combo!
However, Injinji socks are still awesome for one thing: if you want to cut weight but still bring camp shoes, you can wear uber-light flipflops in camp and still be able to wear socks for warmth!