Things are still in the planning stages, but you should be able to get just as involved in the political situations in all routes - a shared factor in all of the demo routes was your Mother turning up and demanding you help her/the Parisi in the coming negotiations, so you'll still have a lot of influence, and how you help will be fairly different in each route with different potential outcomes.
When I wrote 'in routes where you are closer to court you will know more of what has been happening in the political situation (at least, at the beginning) than if your character has been living outside of Segunda for the last two years' I was more referring to how you have a little bit more inside knowledge of how the King has been behaving in, say, Guill's route, that you do in Charlotte's for example.