dado_maker,

This seems to work if I understand your objective.  I am sure it is rough,
rough, rough and perhaps a master will be along to offer improvement.

Sub ScratchMacro()
Dim oPara As Paragraph
Dim oWord As Range
Dim i As Long
Dim myWord As String

myWord = InputBox("Enter the word to find.")

For Each oPara In ActiveDocument.Paragraphs
 i = 0
 For Each oWord In oPara.Range.Words
     If Right(oWord, 1) = " " Then oWord.MoveEnd Unit:=wdCharacter,
Count:=-1
     If LCase(oWord) = LCase(myWord) Then
       i = i + 1
       oWord.Collapse Direction:=wdCollapseStart
       oWord.Select
       'insert field, reset sequence to 1 for first occurence in paragraph
       If i = 1 Then
         Selection.Fields.Add Range:=Selection.Range, Type:=wdFieldEmpty,
Text:= _
         "SEQ WordNum \r1", PreserveFormatting:=True
       Else
       'insert field
         Selection.Fields.Add Range:=Selection.Range, Type:=wdFieldEmpty,
Text:= _
         "SEQ WordNum", PreserveFormatting:=True
       End If
       'superscript the sequence number
       Selection.MoveLeft Unit:=wdCharacter, Count:=1
       Selection.MoveRight Unit:=wdCharacter, Count:=1, Extend:=wdExtend
       With Selection.Font
         .Superscript = True
       End With
     End If
  Next
Next

End Sub