Donovan,
The Maine 2 footers didn't have Yard Offices like the MCRR or BAR. For one thing they had smaller yards and switch moves were often dispatched from the depot. There were yard/shop offices at Wiscasset, Phillips and Bridgton but we don't know how much control of the yard each one had. I know of no interior photos except the Phillips shop pictures in Two Feet Between The Rails and the WW&F shop views in Two Feet To Tidewater. As John noted, a roll top desk may be a bit much for a shop office. If you want more you could broaden (tough word for us two footers) the scope of your display to include the type of things found in the agents office. Consider that the SR&RL main office was right there in Phillips and controlled mainline and yard moves and the WW&F dispatched from it's Wiscasset station. This means the "Yard Office" was actually the dispatcher/main office. With that in mind you could have the roll top desk, candlestick phone, a nice wall regulator clock, track/yard map, red and clear hand lanterns, etc.
Stewart