My next step is to cut to size the ribbed styrene strip that will go into the top half of the body. I followed a similar proceedure to that which I employed on the door. I used my X-Acto knife to cut the approximate shape, then used files to take it down to the proper size.
Here's the body prior to the styrene strip:
You can see that I've also done some putty work on the top part. I just laid in a little tiny layer to hide some blemishes and un-evenness.
Here is the piece of styrene after it is all trimmed to shape and inserted.