Your suggestion is good. I have a RH Linux virtual machine that is configured the same way as my production server - apache config, app versions, etc - that I use. If it works on my VM it should work the same on production. The VM is a little more work but I like being able to access it on the chance I don't have internet access.
I guess it really come down to preference.
"A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools."
-- Douglas Adams
Do you know where and what exact config of your production server will be/is?
Try to match as close as possible setting on your QA/testing environment to your prod server.
That would be your best testing ground.
And keep in mind that best QA is a kids: if they do not break it, none ever will ...