I know this is an old thread, but just in case anyone else finds their way here like I did while looking for other ways to do this...
You can customise the Navigation options via the registry.
HCKU\Software\Microsoft\Office\15.0\Outlook\Preferences
contains three settings which correspond to the 'Navigation Options' in Outlook 2013:
ModuleVisible15
controls which of the options are visible to the user.
NumBigModulesAB
controls which how many items are shown (the rest are hidden within the '...' button)
ModuleOrderAB
controls which order the items show in, with the first being default shown upon opening Outlook.
For example, I have used a Group Policy to deploy these settings to end users:
"ModuleVisible15"="0,1,1,1,0,1,0,0,0"
"ModuleOrderAB"="5,2,3,4,6,1,7,8,9"
"NumBigModulesAB"=dword:00000004
Which sets the visible items to 'Folders', 'Calendar', 'People' and 'Tasks', with no other items inside the '...' (the rest are hidden as we don't use them in our environment anyway).
Since 'Folders' is first in the list, it is the default for users when they open Outlook.