In Excel, can I get historical data across the columns instead of down the rows?

Yes, you can transpose the data using the  formula functions to have historical data across columns. Append "TRUE" in the last part of the Quandl formula.

To get historical prices of Apple (AAPL) across columns, for instance, use the following Quandl formula:  

=QSERIES("EOD/AAPL",,,,,,,,TRUE)