Travis,

You can specify which cell (row, column, rowspan, columnspan) that you want to put your data in.  So I would iterate thru the nodes increment the row and column to create the hierarchy positioning in your worksheet.  If your nodes are showing more than one property, you could iterate thru the columns as well.

I'll attach my sample which will give you the basics.

Our documentation will  give you more details about how to use the Infragistics Excel Engine to create a Workbook.

http://help.infragistics.com/doc/WPF/2014.1/CLR4.0/?page=WPF_Infragistics_Excel_Engine.html

Please let me  know if you have any questions.