Controlling the game with a gamepad is very complicated since there is for example no keybind to accept quests and turn in quests at all; it has to be done with the mouse cursor.
LOTRO plugins are also very limited in what they can do and there is none that can offer support for GamePads.
You should check out the options Steam gives you for mapping a controller, many people have experimented with controller layouts there - it is a bit hidden since the controller config is meant to help with Big Picture mode first.