I've made numerous lapghans like this using 2 strands of worsted weight yarn, and US #10 sized needles. I always run a variegated yarn together with a solid to create the shading within the stripes.
To fill in the holes of Feather and Fan, I wrapped the yarn backwards in the Yo's... not really sure what this is called. Since I knit Continental Style, wrapping that yarn backwards is really quite easy.
This was not one of my better efforts, but the cats really like it.