Quite an adventure! You only get to be new to all of it once. Congrats on getting that one draugr at least. Buzzing noises that don't come from your own beehives is always bad news.

If you saw a kraken on YouTube, it was a mod, because the vanilla game doesn't have them. There are sea serpents, but encountering one on a sunny day is very rare. They usually come out at night or during storms. There are also leviathans which are living islands and no threat at all, unless you annoy them and aren't prepared for a swim.

Sailing past dangerous biomes isn't too bad if you keep your distance. For reference, I usually sail at a distance where the land barely shows on my mini map. If it looks dangerous I might go out a little further, just as long as I'm out of aggro range. Sometimes that does put you in the ocean biome, but as I said earlier, serpents are very rare on sunny days, and if you get the wind behind you, you can probably outrun them.

Chances are good that you will have to sail past dangerous biomes when you go places, but it's doable if you are careful. Just make sure you find a good place to park before nightfall and plant a quick portal so you can sleep in your own bed. (You definitely haven't found all of the black forests on the map. They can show up all the way to the edge.) So go ahead and give sailing another try.