If pulling a cable through the wall is a problem, the second best thing is a powerline set that runs your network over the power sockets. one adapter by the router up front, one in the back room.
Not as good as the cable plus access point in the back room.
But still a better solution than a wifi repeater, because the back room no longer depends on the signal making it past the bean shelves...
You would still plug the printer into the adapter at the back by cable. So you get the same "printer on its own cable" win as in the earlier reply, just without drilling through the wall.