I was looking at the New Balance website and found a section devoted to lacing for a better fit. Mind you that this is for running shoes, but the concepts may still hold. There are examples to mitigate heel slippage, toe problems, high arch, narrow heel/wide forefoot, and eliminating pain on the top of the foot.
Comments
Best of luck on your trek! We'll be watching your progress and wishing we could be on vacation too (Notice I didn't say "on the trek too" because that's just too much fresh air for us!)
Love,
Kathy