any common ship travel would definitely be coast hugging. They probabyl dont' ever leave sight of the coast, due to sudden storms, unless they have to. It would be dangerous, even in ships that can handle it.
But because of hte storms, I believe travel by foot/horse would be much more common than it was, say, in the Roman Empire around the Mediterranean. Ships are faster, sure, but if you're not hauling goods, the safety factor is huge. Yeah, there's a lot of sea travel (near the coasts) though. I'm not suggesting that there's even LESS sea travel than by land. Just that there's a lot of land travel too.
Probably there's going to be a network of roads in most nations to get from place to place.
I think there aren't; that many cities right on the southern coasts, for reasons of the weather, mostly. In the north, they're there because people've only been there for half a century, they haven't gone that far inland yet.
So, anyway, that's what i think. I don't think sea travel is 80%, maybe 60%, just because of the nature of sea travel.