Expert advise on working Fair Isle in the round:
From Mary Jane Mucklestone: Fair Isle in the round is easier than on straight needles because you always see the pattern from the right side and can watch it grow. When I’m working on dpn’s, I divide the stitches so there is a full pattern repeat or two repeats per needle. I organize the increases or decreases around the beginning/end "seam stitch.”
Remember to carry the yarn loosely across the back. Have fun. Sing little songs with the number combinations to help you remember the pattern.
From Kristen TenDyke: Knitting Fair Isle in the round speeds up my work. Many people (myself included) have a harder time holding two strands of yarn while purling than while knitting. When purling, I'm constantly having to rearrange the yarn so working a purl row takes about twice as long as a knit row. Knitting with two strands is easier because the yarn is in the back of the work.
Also, because of all the yarn-futzing on the purl rows, stitches can be uneven. Working in the round with the knit side always facing keeps the stitches more consistent and the fabric more even.