Have used four types of worsted/aran yarn in both acrylic and wool for this pattern and found they all worked well. Would suggest casting on 200 stitches or some other multiple of four stitches instead of the odd number indicated in the original pattern. To make your scarf longer or shorter than the pattern indicates, the first part can be knit over any multiple of four stitches like this:

row A: K3, wyif sl1p; repeat to end of row.
row B: K1, wyif sl1p, K2; repeat to end of row.

where k is knit, wyif is with yarn in front, and sl1p is slip 1 purlwise.