I got some more work done over night.
After gluing the top pieces together, there were some gaps so I used Hobbico HobbyLite filler in them...you can see the filler in the seams in this pic. This filler is fantastic for use on foam as it completely adheres and sands smoothly. This shot is of the underbelly of the lid...
And here's a couple of shots of the painted base. It's about finished now...
I can't speak highly enough about the HobbyLite Filler for working with styrofoam. I've used it on my tombstones as well.
I've also made corner brackets out of Crayola Model Magic which will be painted black and glued onto the chest sides with Elmer's Wood Glue...