There’s some info here that may help:
http://bobsguides.com/revolution-permissions.html
Probably the simplest way is to duplicate the Administrator policy (call it ReviewAdmin) and edit the duplicate to remove the publish_document permission.
Create a role called "Reviewer" with an authority level of 5 (or any number higher than 1).
Then assign your user to the Administrator group with a role of Reviewer and a policy of ReviewAdmin.
Once it’s working, you can edit the ReviewAdmin policy to remove any other permissions you don’t want the person to have (definitely take out access_permissions). You can hide the file tree and the element tree by removing the file_tree and element_tree permissions.