Hi Steven,
All WPF / Winform controls in NOV are actually NOV hosts that wrap a certain NOV Widget. This Widget is exposed from the typed Widget property of the control. In the case of the "NRichTextViewWithRibbon" control this Widget is of type NRichTextViewWithRibbon. This widget in turn contains View and Ribbon properties that expose the functionality of the ribbon and the rich text view. So back to your question in oder to load / save content from the view you need to write something like:

nRichTextViewWithRibbonControl1.Widget.View.LoadFromFile("c:\\temp\\test.rtf");

You can also import rtf/docx etc. from in memory streams (this is the case when you read the content from a database for example):
nRichTextViewWithRibbonControl1.Widget.View.LoadFromStream(someStream, new NRtfTextFormat());

Hope this helps - let us know if you meet any problems or have any questions.