Locking a door is easy enough, but what about terminals?
Basically what I am doing is placing a hard lock, and I want a terminal with an average hack that has the option to open the hard locked door.
My plug in is aimed at higher level characters but for necessary doors I want more then one option of opening it just in case a player has a lot in hacking and average unlocking,vise versa etc..

There are a couple of ways you can do it.

1. You can hardcode it.
Look at terminal 'Hubris03Terminal01' at option 2, Unlock Foreman Door. The script result forces a door with the reference Hubris03GeneratorRoomDoor01REF to unlock.

2. You can set 'linkage' from the terminal to the door and in the script, get the linked objects reference name and unlock it.
See the terminals like 'DefaultUnlockTermWALL2Average'.

Just as a minor addition, if you need exact step-by-step help you can take a quick glance http://geck.gamesas.com/index.php/gamesas_Tutorial_Non-NPC_population#Unlocking_Doors_and_Containers_With_a_Terminal. It is part of a handy beginner's tutorial on the GECK website. While it isn't the most in depth tutorial, it gives you some general info on how to do several things.

As Willie stated, you would want to use DefaultUnlockTermWALL2Average instead of the DefaultUnlockTermWall3Hard listed in the tutorial.