baronreads, you can use ANY washable worsted weight yarn. Plymouth Encore or Lion Brand Wool-Ease are good choices. Some people are using Caron Simply Soft, and there are even a few people that have chosen to use up their Red Heart Super Saver stash!
And you can choose ANY STITCH and ANY COLOR you want.
BostonBecca, I'm not sure of the yardage, but most people have only had to use one skein. If you want, you can do half of your section with one yarn, and the other half with another yarn. Have FUN with it!