You will still get the usual random events like skeleton surprise and such. But for actuall boss related raids/events it is dependent on were you have set up your base. The boss related event for the Mistland boss does not happen if your base is inside the meadows biome. If your base is in any of the other biomes (Black Forest and onward), you will see a specific event/raid for that boss. Also as mentioned by NiceGuy. There is also a event that triggers within the Mistlands biome should you decide to build a base right there. If you plan on building bases in other areas do plan on better base defence. Though the event has been nerfed a little in the last update. It is still dangerous if you are unprepared. I don't want to spoiler too much, but there are ways to exploit enemy pathfinding for this. There are videos you can look up if you don't mind spoilering yourself.^^