Premiere Pro :: Exporting A 1080 HD Project To DVD?

I am on the final stages of finishing my first ever HD project, having made the jump Premiere Pro 2.0 to Premiere CS5.  Mid-way thru I found it necessary to upgrade to Creative Cloud, so that is where I am working now.  The HD world is so vastly different from the old SD flow that every single step of this project has been a huge learning curve for me.  I am basically an 'oldie' but for all practical purposes I am a total 'newbie' at this. That said, I am now finding myself ready to export my project to DVD in a SD form with Stereo sound. 
 
I am working with footage shot on the Red Epic.  At my current stage I am working withh ProRes 444 renders from which I have created a full nested 74 minute timeline.   Frame rate is 23.976 and the source is1920x1080 with 1.0 square pixels.
 
So now my movie is done, and it looks and sounds like I want it to. The question now, in a nutshell, is what file type and settings should I use to export my movie so that I can retain aspect ratio?  Should I output a movie first or take the project into another program like encore first and make my disc from there?
 
Also, I have my first screening coming up (primarily for cast and crew and industry insiders) in a couple of weeks, so I need to create a 1080 HD File with my 5.1 surround track that I project from a laptop.  The screening venue has the capability to do that via a simple HDMI cable hookup, but does the laptop I use need to have any special capabilities to do the job?  And what is the best file type to use for that?
 
I have always been more of an artist than a tech head, but I am pretty much doing the whole post on this movie alone, with the exception of the Dissolve renders and the sound design, which I had done for me (I have a great finished 5.1 design in .wav format, as well as a stereo version).
 
I should also mention that I currently have Encore CS5.  Can I work with this on a Premiere CC project?