Hi SteveM,
I have created sample for your requirement.There is no direct method for save/print the Crop Diagram.We can save the crop diagram using some other logic or methods.
The functionality of the sample is to Save the selected nodes in the diagram.Before click the save button in the sample you should select what part of diagram wants to Save.Load button loads the diagram which you saved before.
Please download the sample from the below link.
http://files.syncfusion.com/support/Diagram.Windows/Forums/F82077/main.htmLet me know whether the above sample meets your requirement.
Regards,
Gowri