Dig a giant cliff around your base, and have your base by the water so you can have your boats ready.

Put the strongest chests with the most inventory slots and put them near your boats. This is the last resort you'll do. Or you could portal away and have your stuff in a different base

My base that doesn't seem to have the ability to experience raids, is right next to the water but the land above my base was a lot higher. I just dug straight down. I don't think Trolls go down cliffs. If they do, they'll sustain a ton of damage

I also fell a lot of trees and leave the logs on the ground to make the pathing difficult for mobs