The model is now about 6500 polys, and I completed the bake this week. I haven't done a clean-up pass on the normal map or the lighting map yet, so you will likely be able to see some of the warping and artifacts.
Instead I wanted to prototype the gridlines on the normal map, and see if it would come out as I'd hoped. Figuring this out is important since I plan to use the same method to paint in the small windows and other details.
I'm reasonably happy with the result of the gridlines in the normal map, though it needs some tweaking.