Build a large city along the side of the Rhine river and defend it from increasingly difficult incursions. Farming may be difficult on the Western side, but some natives could be encouraged to let you farm on their side of the river. Beware those that would however disagree with the notion of being civilized.
This is a scenario with a goal of surviving 30 years while building up your city. Things really heat up after 25 years so be prepared to fight hard to defend what you have built up. All other goals have been disabled. While testing I found that the conclusion of this map would be fun with a survival aspect.
I'm decent, but far from an expert on the game. I believe it is beatable on Very Hard but please put in a comment if this is not the case.