Must be logged in as an admin to make these changes.
1. In Group Policy Editor (gpedit), I had to disable the policy for drive redirection at:
Computer Configuration > Administrative Templates > Windows Components > Remote Desktop Services > Remote Desktop Session Host > Device and Resource Redirection
2. Find the most recent SU RDP file that had been downloaded, right click and open in Remote Desktop.
3. In the window do the following:
click "Show Options" -> "Local Resources" tab, ensure "Drives" is checked, and verify drive mapping under "More..."
4. Remember the setting and complete login.
5. Have the user test the usual login path for accessing SU. RDP window may pop up, if so have it remember options.