This should be in the MTW2 guides I think.
I usually do similar within 16 turns but I'm also taking some pieces of the rebel towns on the continental.
Scotland usually starts off slow so if your fast, they won't be able to mount an effective defense. I've seen parts in the later game where they actually become a strong nation but that's only because the English AI didn't bum rush them. In fact, at the start start leveling up your spy. If you do it right, you can take out scotland in one turn and the pope wouldn't give a crap. Since the spy opens the gates for you and the scottish army usually stays outside monitoring the area.
France is pretty good in honoring their alliances, especially if their marriage alliances. Just keep a strong garrison in the area and they'll be good boys.
If I might add, you should also try and capture the towns north of Denmark, if your lucky, the Danish might not have captured them yet.
This effectively takes out an opponent that could seriously challenge you later on.
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