rust on a roof.

I have recently a purchased 10 year old mobile home with a galvanized sheet metal roof. There are a few patches of rust on the south side north is fine. Question is what kind of preparation do I need to do on the patches before using a roof coating or can I just paint over the patches. Also I was told that it is not a good idea to walk on a mobile home roof like you can on a regular house roof. Is this correct?
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