I am still in the guild I am just working on levling some of my other toons so that I can take advantage of their professions.
Keep in mind, if you'd like, you can get your alts into the guild, even if it's just for the company while you fuck around doing whatever ;)
Indeed, why not bring your alts into the Guild so that the entire Guild, as well as you, can take advantage of their professions. You could also take advantage of any lower level stuff that the Guild doesn't need to speed up your leveling. It's a win-win.