Not sure if I have interpreted you question correctly, but this should help you to set the model document iProps from the idw. You could uncomment first 2 lines to access it through the sheet views if you have a multi page drawing with different model docs.
'doc = ActiveSheet.View("VIEW1").ModelDocument
'modelName = IO.Path.GetFileName(ActiveSheet.View("VIEW1").ModelDocument.FullFileName)
doc = ThisDrawing.ModelDocument
modelName = IO.Path.GetFileName(ThisDrawing.ModelDocument.FullFileName)
strStockNumber_DefaultEntry = iProperties.Value(modelName, "Project", "Stock Number")
strDescription_DefaultEntry = iProperties.Value(modelName,"Project", "Description")
strStockNumber = InputBox("Enter Stock Number", "Data Entry", strStockNumber_DefaultEntry)
strDescription = InputBox("Enter Description", "Data Entry", strDescription_DefaultEntry)
iProperties.Value(modelName, "Project", "Stock Number") = strStockNumber
iProperties.Value(modelName,"Project", "Description") = strDescription
iProperties.Value("Project", "Stock Number") = strStockNumber
iProperties.Value("Project", "Description") = strDescription