I think you're going at this backwards. Counties can play with using their liege's armies to do things, but there's no need (in fact, almost no ability) to conquer anything.I did a look over of all of the counties in Veld's alternate "Stamford Bridge" scenario
Well, find a count or a dynasty you like, and let's fix that.Since nobody really does gameplay AARs, I've never seen [opportunistic marriages] in action and don't have a good grasp on how to do it
You will find that it will require some patience. There are very few 1066 heiresses and pretty much everyone with an interest in such things goes after the heiress to Aquitaine, which at the time was the richest part of France. Other than her, you pretty much have to wait until at least (1066 + 16 =) 1082 for the first batch of game-produced heiresses to mature.
Then again, Aquitaine could be fun: France, Provence, Spain, Brittany, England are all pretty close at hand and you can start with whatever culture liege you'd like. (Basque? )
Although it varies from patch to patch, it's generally suggested n00bs stay away from Spain. It's only slightly less masochistic than Nubia, especially if you're not the king and able to direct all of your armies.Porto (Porto and Castelo Branco)
might be a lot of fun, but the Hautevilles are one of the few dynasties that start vanilla CK with a salic law: you simply can't inherit until they change it. You'd need to look east or west for marriages or be willing to reload a lot as your king steals your sieges in Sicily and Tunisia.Reggio (Reggio, Messina)