You can find green screen panels that come in different sizes and shapes here: http://sfmbox.com/green-screen-props/
but I don't really understand your question? You can just open your map in SFM and do what you do, render it out and key it...

I'm filming a real person in front of a green screen and then keying them into the map, or atleast that's the plan... lol.

Well, Jimer Lins has a playlist on one way to use motion capture (I haven't actually looked at the videos yet to know if they're anything close to what you're talking about), but as ASZ20 said--if having the order backwards--your best bet is probably to render your video first and then add the live actor on top of the resulting video in post-production, using whatever external program you're comfortable with. Source Filmmaker isn't like a standard video editor--think of it as being closer to creating a virtual world to record in than working with video files. While I'm sure there's some way to import your actor, but he or she would be restricted to a 2D plane, and SFM's strength lies in its ability to (relatively) easily animate in 3D.