Yea of course you can do the job yourself, and no there is no way to close the hole, the power steering line there is under pressure.
So changing it yourself, rating it from a 1-10 scale...? it's about a 4, I personally think the hardest part is unhooking it from the bottom of the power steering pump. That nut on the bottom can be hard to get at, it might be easier to take the power steering pump out to get to that nut.
Do you have a Haynes manual for the car to help when taking it apart?
2000 SE wagon 2.0l Zetec.