While price data is easily available, total return data is a bit difficult to find free/open sources for. I am not looking for some massive data set that goes back to Galilean times, or covers small caps in tiny economies. I just need last 50 years or so of US S&P 500 or similar large cap stocks.
I think you are searching for "Dividend Yield", which can be added to any gains or losses to give the total return.
For "total return" maybe you mean "earnings yield"
Robert Shiller has monthly total returns of the S&P 500 going back to 1871 on his website at Yale: http://www.econ.yale.edu/~shiller/data.htm