I decided to do it as a non-opening model and have painted it red. To avoid the inevitable frame sag I attached the wrecker body to the back of the sleeper, leaving a small gap, and now the wrecker body, sleeper, cab, and hood are all one unit that can be attached to the chassis when the rest of the work is done. I haven't assembled the rotator or any of the tow hardware and I've only put some of the chrome on.
Unfortunately for various reasons this project may go the way of my 1/16 wrecker project and get sold or traded off in it's current yet-to-be-finished state. Maybe I just wasn't destined to do a big wrecker in any scale!