Well, some would say that what you’ve described isn’t “simple”, but yes, that’s all you have to do!
As I said in my original reply, you can do it through the mirror via a dreamhosters.com subdomain as well, though there is the possibility that the original domain as configured in the web application will “leak” through and cause trouble. The url munging that the mirroring does should catch all obvious instances, though. The methods are compatible so you can give both a try and report back!
You’ll notice that the wiki article that Patrick pointed you to does actually describe a third method - adding the Dreamhost name server as your primary nameserver on your local machine (at home).
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