I recommend against doing that.
First of all, assuming she is running iOS 6.0.1 (current release) on her iPad, she does not require any laptop to do a setup. Check especially the "Get Started" tab of this: http://www.apple.com/support/ipad/
If you do use your laptop, there's too high a possibility of mixing up information in my opinion. Say, for example, you use her Apple ID in iTunes and authorize your computer that way before the setup. She'll still get your iTunes music (by default). That's just one simple example.
Especially if she sets up an iCloud account, over-the-air setup and maintenance sound far more preferable to me.
If you want to give your sister the iPad and set it up as new, the restore it as new. You can either do it through iTunes on your laptop, or directly on the iPad, via wifi.
iTunes: Backing up and Restoring iOS software
You do not need to use your laptop at all in order to setup your sister's iPad. I would set the device up via WiFi. If you know here Apple ID and password, its a breeze. Even if you do not know that information, it can all be entered later when she begins to use the device.
This was relevant and written for the iPad 3 but it is still the same basic setup on the new iPad with Retina display.
My recommendation is to just get it up and running for her. She will have to do so much customization on it anyway. Frankly, I think that a big part of the awe and wonder of getting a new iPad is the setup process and I believe that you cheat the recipient out of a really cool experience when you don't let them set it up themselves. Just my 2¢.