Basically you want content editors who have no rights and who will not be able to mess things up and who will not be confused by all the options in the backend. So create a content editor login who can only view and edit pages, nothing more.
Then find the following files in /cms and change them.
# CMSMain_Content.ss
Instead of <% include CMSBreadcrumbs %>:
<% if $CurrentMember.inGroup(2) %>
<% include CMSBreadcrumbs %>
<% else %>
<a href="/Security/logout">LOGOUT</a>
<% end_if %>
Last two links:
<% if $CurrentMember.inGroup(2) %> ... <% end_if %>
Instead of $Tools:
<% if $CurrentMember.inGroup(2) %>
$Tools
<% end_if %>
#LeftAndMain.ss
Instead of $Menu:
<% if $CurrentMember.inGroup(2) %>
$Menu
<% end_if %>
#Add edit this page and logout link to templates of pages that may be edited.
<a href="admin/pages/edit/show/{$ID}" title="edit this page">Edit this page</a><% if CurrentMember %> | <a href="/Security/logout">LOGOUT</a><% end_if %>
These notes are based on the idea that the admin group is group 2. And it was tested with 3.0.2.