Awesome map. Super impressive. Is any of this work going to show up in the form of tutorials on the mapping center website?
We did do a technical article in Cartographic Perspectives, Number 56, Winter 2007.
There is a style file with various symbols and fills and other elements on the Mapping Center site ArcGIS, Resources section (go to http://mappingcenter...sources.gateway and click the Styles tab if it's not already selected. Look for "Historical".
If you have questions about specific techniques you can post a question on the Mapping Center's Ask A Cartographer section (or let me know).
I think, as with other design considerations, a lot of it comes down to some pretty simple things like fonts, colors, and maybe a few symbols and effects. The tools used to achieve that are of much lesser importance, although they do figure in when it comes to the how. Some tools probably make it easier to do certain things than others, but some of that might come down to personal experience and preference. I'm sure similar maps could be made with many graphic apps, as well as other types of applications. So for me the key is not so much in how do you use a specific tool to create an effect, but is rather in figuring out what effects and fonts and colors will achieve the desired design. So that's a good excuse to spend time perusing old maps if you're going for a particular period look.