What you need to remember about the show running-config command is that the user running the command will only be allowed to see what they are authorized to configure. Keeping that in mind and so the tripwire user account can see "all" the running config, create a rule to allow this Tripwire user to authorize at the privilege 15 shell level and then apply a special limited command set (which you will need to create) that only allows the commands that the account needs to function.
Hope this helps!
Greg