I always liked this one:
http://www.fonsandporter.com/article...-quilt-project
It was in their magazine, the month and year listed. Maybe a friend has the magazine if you don't. It is a little different than most log cabins and it isn't just fall colors. The blue kind of breaks it up. Maybe you could find a purple or teal to jazz up the fall colors? (Not sure if you are doing batiks, but they have some beautiful colors that blend with the browns.) If you go to the free patterns section (top left) then down to log cabin quilts, there are quite a few layouts. Some are square, but you could add another row or two to enlarge.
Also, Judy Martin has a couple log cabin books that have some really nice layouts, as well as pinterest.
As far as arranging the colors, I would make piles according to value, and use darker on outside of block, lighter inside. You can take a b/w picture on phone of the fabrics and you will be able to see which strips have darker values vs lighter values.
Don't forget to take a picture of it for us before you give it to her. We want to see!