You might try diabetic socks. We looked at all possible items of clothing for what was supposed to be a wet and rainy trip to Ireland starting May 18, 2012, but ended up to be very warm (80 deg) and sunny.
Several months before our trip, I looked at different items of clothing that would dry fast if I had to wash sweaters, thick socks, jeans. I found anything that had some polyester or even nylon even if mixed with cotton dried a lot faster than 100% cotton. My acrylic/cotton sweaters dried overnight or in a few hours; diabetic socks dried a lot faster. But, we usually washed them early in the evening, and before bed I would turn them toe up and by morning they would be dry. These items are also lighter in the suitcase. Diabetic socks come with thick soles, but still light. They are available in major chain drug stores like Walgreens/CVS, but I also bought them on line from Carol Wright or other junk mail catalogs, like $4.99 a pair, or 8.99 a pair. Hope this helps