Now that I have taken everything apart, I was looking at the upper deck and decided to make an access door. The engine cover looks like the logical choose, using a sharp knife I cut repeatedly along the edge of the engine compartment. The corners were a little harder, but I have seen that other people use sewing yarn to cut small areas of plastic, to my surprise it works well. It can be a little tricky to keep a constant tension. In this photo you can see how this turned out.