I'm not so much for the number crunching, myself. Before I picked up the Mage header, I barely cared about CP because I mostly just roleplayed with everything. I do agree that if you're going to pick up Mage, you should be prepared to throw a lot of CP at it. I would also recommend casting practice between events, as it's a lot more fun when you can actually hit things and make them fall down. I don't remember where you live -- if it's at all near me, I'd be happy to meet up and we can practice chucking packets at each other.
Since it looks like you're thinking of Mage partly because you're not up for lots of combat, I would definitely recommend getting the Staff skill. I don't have it (they simply don't go with my outfits), but without one, that means you're going to do a lot of running around. I mean
a lot. As in, your only form of defense is scampering out of the way, ideally behind some friendly fighters. With a staff, you can hold it while you cast, which means you can block more easily and don't need to resort to the time-honored "where the hell did I drop my sword this time?" technique.
As for Alchemy, I don't have it at all. That's not because I don't think it's useful, but because I have a personal aversion to any production skills. I'm just not good at scrounging for tagged items in game. I do think that having someone in Greyhook with Alchemy would utterly rock, and if you decided to go for it, I would happily throw any alchemical components at you that I managed to stumble across. There are lots of great things you can make with Alchemy (and it gets even cooler if you become a Battlemage
)
Despite the CP-intensive nature of the header and the unpredictable vagaries of packet-throwing, I really like playing a Mage. If you decide to jump on that particular Resonant grenade, I promise to drag you into all sorts of Magey goodness with me if you're up for it.