Hi Keith,
Thanks for choosing Syncfusion products.
We do have the AppStateSerializer's SerializeObject/DeserializeObject methods to save/load any control on a form.
Please refer the below sample.
http://websamples.syncfusion.com/samples/Tools.Windows/F75831/main.htmWhich shows how to do this on a TextBox. This can be adapted to the TreeViewAdv as well.
Please let me know if any concerns.
Regards,
Hema