Other than GC + passport, you don't need any further documents.
Wac-ed_in_CA,
It is usually complusory/customary for the immigration officers to 'welcome' you back. Most times they are good about it, not sure if it matters whether you are a citizen or just a PR, but I guess I would be more relieved that I don't have to go through the uncertainty that I have had in all my entries so far, whether they will allow me in the country or not. No idea where that fear comes from but it has always been part and parcel of my entry process.