Electrical Service - Existing Cabin Electrical Setup

The cabin is currently wired for electricity.  I took a few pictures of the electrical equipment today for planning purposes.

The exterior electrical box receives three 4 gauge wires from the electrical meter at the front of the property.  There is one 150 amp breaker in the panel.  In this picture, the front of the panel is off.  However, when it is in place, you can access the switch and easily turn off all power to the cabin.

This is the interior breaker box which is almost immediately directly behind the exterior box.  The panel has room for eight different breakers but only four are currently used.  One is used for the lights, one for the plugs around the walls, one for a dedicated plug for a window AC unit, and the last for a dedicated plug for a fridge.  

I'll need to decide if I will mount the electrical meter to the cabin and how I want to create circuits for items outside of the cabin.  I'm not sure that I need many circuits outside the cabin but I want to plan for additions later.  I might want to add a large light, run a power line to the shed, or who knows.  Better to do it right the first time than keep doing it over again in the future.