I did cloth on my RAF teams at level 52 or 53, which ever the first level is you can do them all. It was good for almost two levels with the RAF bonus. I agree with others, save your cloth if you are already 59. All the cloth for 4 toons x 5 (15 stacks of each * 4 - 60 stacks of wool, silk, mageweave, runecloth) factions could pay for epic mounts if your server is anything like mine.

And even if you don't hit HFP right away, the WPL and EPL quest will ding you in about an hour. I did it both ways and actually preferred staying in Azeroth simply because it saved the higher XP mobs, instances and specifically quests for when I no longer had RAF. Sure it costs about an hour from 58-60 up front but it made up for it on the back end I think.