This should work easily. Make the scarf first to familiarize yourself with that cable pattern, which by the way, is easier than the one in the Knitty hat.
When you make the hat band, CO only 14 sts, and instead of the (K2, P2, K9, P2, K2) in the hat band pattern, you are going to (P2, K2, P6, K2, P2) in row 1, and (K2, P2, K6, P2, K2) in row 2. Cable 3F on the 6 middle sts in the 8th row, and repeat. Since the knitty cable pattern is also an 8-row repeat, its perfect....do the same number of repeats the pattern suggests for the size you are making, either 16, 17 or 18.