For future reference, here's what I ended up doing...
<HEAD>
<!---------------Resize & Move Window------------------------------>
<script language="vbscript">
window.resizeto 460,255
screenWidth = Document.ParentWindow.Screen.AvailWidth
screenHeight = Document.ParentWindow.Screen.AvailHeight
posLeft = (screenWidth - 460) / 2
posTop = (screenHeight - 255) / 2
window.moveTo posLeft, posTop
</script>
<!---------------Application Info---------------------------------->
<TITLE>GAL Picker</TITLE>
<HTA:APPLICATION ID="MyApp"
APPLICATIONNAME="My GAL Picker"
BORDER="Dialog"
CAPTION="Yes"
SCROLL="no"
MAXIMIZEBUTTON="Yes"
MINIMIZEBUTTON="Yes"
SHOWINTASKBAR="yes"
SINGLEINSTANCE="no"
SYSMENU="Yes">
</HEAD>
<BODY>
<body STYLE="font:12 pt arial; color:white;
filter:progid:DXImageTransform.Microsoft.Gradient
(GradientType=0, StartColorStr='#000000', EndColorStr='#0000FF')">
<SCRIPT LANGUAGE="VBScript">
'''''''''''''''''''''SUBS''''''''''''''''''''''''''''''''''''''''''
Sub GALPicker
Dim objWordApp
Dim strEmailName
Set objWordApp = CreateObject("Word.Application")
'new line of code proviced by Bond, adjust file path as needed
CreateObject("WScript.Shell").Run "C:\Users\JohnDoe\Desktop\activate.vbs", 0, False
strAddress = objWordApp.GetAddress(, "<PR_EMAIL_ADDRESS>" & " ### " & "<PR_DISPLAY_NAME>", False, 1, 1, , True, True)
If strAddress = "" Then
Exit Sub
Else
End If
msgbox strAddress
MyGal.Value = strAddress
End Sub
</SCRIPT>
<H2>My Outlook GAL Picker</H2>
<P>Add Email Recipient:
<input type="text" name="testGAL" id= "MyGALTest" size="36" onfocus="vbscript:Call GALPicker">
Then I created a new .vbs file per Bond's recommendation...
Set Shell = CreateObject("WScript.Shell")
' Try to activate the GAL window for 10 attempts/seconds...
For i = 1 To 10
If Shell.AppActivate("Select Name") Then Exit For
WScript.Sleep 100
Next