The point where it gets urgent is when the artifact is brought to the college, and I find it more RP-realistic to assume that takes a fair amount of time. The Psijics may be able to do it rapidly at the end, but they're not doing it the first time. So take your long break when that happens.
If I were re-writing the quest line, that's where I'd add extra quests. More research on what that thing is, before it's moved from it's current location, would be prudent, wouldn't it?
And the things that happen after that point aren't really related to your being a mage, so much as someone who can do something about the crisis. Since retrieving the key implement is actually easier for someone who's not reliant on spell-casting, why worry that you haven't advanced your mage skills?