Hi. I will try to make and post an Claculator file of whole Roxbury. Each player will get a certain amount of material to build walls, holes, spikes, etc.
Then he posts a file with the changes (or just coordinates) and I will combine it into a final 'trapped' map of Roxbury.
That actually sounds like a really cool idea I may steal that for a future scenario I'm running with my table top group. It sounds like a lot of work for you tho I don't want you to put more into it than is needed. But having a set amount of materials and specific things we can do with those materials might help organize out defenses and spur creativity.
As long as you don't mind it WD I am all for this idea.