If you are using Ping do not setup the repository until the PC hosting the repository is at its final resting spot.
We found out the hard way when setting a a file/print server that was also going to be a repository. We setup the server in our HQ and then sent it out to the branch office. We of course test the repository to make sure it work when it was here. The problem being is the repository list changed which force all the clients to re-ping the repository's to see which one was quickest. All the PC's in the HQ building picked the new server. Well when we shipped it out, all those PC's still checked into that server because the sitelist did not change nor did the clients IP address. The only problem is now it was across the country.
Lesson learned we now use a set list for the repository and tell it which repository to use. No longer hope Mcafee picks the right one.
In your Agent Policy for Repositories you would use the "Use Order in...." and disable all repositories but the local one and the ePO repository. This way say you have a site in CA. That site will only receive updates from the local site in CA and if that is not available then they will receive updates from the master repositories. We no longer let Mcafee pick the site. It is not reliable enough for us.