For your part about not having rights on certain databases, I found this at http://www.techques.com/question/19-12904/Error---Get-SPWeb-in-Powershell
The account will need permissions on the content database. Just executing:
Add-SPShellAdmin CONTOSO\User1
Will give you access to the configuration database, but not the content database. Also provide access to the content database by giving access to the content database by using the -database parameter
Add-SPShellAdmin -UserName CONTOSO\User1 -database 4251d855-3c15-4501-8dd1-98f960359fa6
You can provide access to all content databases and SharePoint service application databases by using a command like:
Get-SPDatabase | Add-SPShellAdmin CONTOSO\User1
