How to patch a closed enviroment using SMS in an enviroment with no internet access?

I have to setup a closed enviroment.  This enviroment will not have access to internet.  I need to keep the workstations in this closed enviroment up to date with all the microsoft patches.  I am planning to use SMS to manage and patch the components in the domain.  

1) What would be the best way to configure and setup SMS so I can bring the patches from Outside via a USB drive?
2) How would I get the all of the Microsoft patches into a USB drive that i can then import into SMS in my close enviroment.

Thanks

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