I think this is a start. You need to include trading also. I created a spreadsheet of lawful trade routes within Gallia and the best run makes 23 million per hour. I guess that is not bad, but it isn't that good either. If it were then more people would be in Gallia trading. It needs to be a little higher if you want more activity.
There is only one commodity that sells for more than 4 million and that is military vehicles from BS Epinal in Lorraine to BS Carcossonne in Languedoc. Then you could take neon back to Alesia. It takes 30 min round trip (Epinal > Carcosonne > Lodeve> Alesia > Lixheim > Epinal). So if you made 2 full trips you are going to make 26 million per hour roughly.
