Hi,
You can use the clientremote.exe in CD2 for deploying the client install package to each site. first of all, export an installation package from SEPM.
Copy the package and the clientremote.exe to a machine at each site [ possibly a server ].
Then, you can either take an RDP and do it, or manually do the following:
Run the clientremote.exe and deploy the package to all the machines in that location.
please note that even if you take an RDP of the deployment machine, which stores the package and clientremote locally, the deployment of client package will be local to that site. Meaning it will not hamper your bandwidth.
Once the installation at each site has finished, you can configure a liveupdate policy to use GUPs at each site.
You can refer to the following articles:
https://www-secure.symantec.com/connect/articles/configuring-group-update-providers-symantec-endpoint-protection-110-ru5
https://www-secure.symantec.com/connect/articles/types-group-update-providers-ru5-release-symantec-endpoint-protection-110
Best,
Aniket