Not real sure what you mean by this? You can only download Madden through Origin. But once you've set up your Shadow Machine, just connect to it then....
A) Install Origin
B) Install Madden
C) Launch Madden and max out your graphic settings and any other settings you wan to customize.
D) Install any Frosty Editor and Frosty Mod Manager
E) Install Mods and launch them via Mod Manager.
Besides price the only major difference between buying a gaming PC and using shadow is your connecting to a Virtual PC instead of hitting a power button on a physical machine to launch it. Once you've connected to your shadow machine it is just like having the computer physically in front of you.