I got Turkeys out of "secret treasures" on the big island. I only got a few and it was taking days to get even one, couldn't get any. I finally got bored and bought the "behind the gate" area and put down a bunch of blue kitty moneyboxes and shoveled out everything in that area and got 4 more Turkeys in one shot! I think my problem was I had already cleared out a lot of the trees and rocks in the main part, didn't have much to dig out other than decorations. Hope this helps!! :)

If you hit "mode" above the storage button, it shrinks down all the trees, big rocks..maybe you can click on things that are behind the big ones? This is very useful for me! Hopes this helps :)

I couldn't tell you what quest line but you get to build/place the boat on the island when you get far enough in it. I just did it this week but wasn't paying much attention to details. I would just focus on advancing all your quests until you get it :)