(Pathfinding) How to take a particular path, while avoiding others on a flat terrain ?

Kindly check the attached image. How do I go about making an object take a particular path from point A to point B. The path is shown in grey in the picture attached. Further questions are as follows:
How do I make sure that the object doesn’t fall down a pit or a cliff ?
How do I make the object avoid the water ?
If the object landed up on the green area, how can I make it move to the nearest grey path area and continue towards its’ destination, instead of making it continue to move to the destination on the green area itself ?

Every box is a single tile with each type as a prefab. So, every green tile is 1 prefab, every path tile is 1 prefab, every tree is 1 prefab.

Kindly point me to the best resources that will aid me in achieving this behavior. In the future, I also intend to include sloped paths, but that will still be tile based. So basically, each tile will probable hold a priority that the object will check before moving over it (or not).

Thanks for taking the time to read this.

You can add a node (Just an empty transform) to each turn, then connect them (Each one holds an array of all the nodes it connects to). From here, you can use an djikstra or A* algorithm so the unit will follow the path.

It won’t fall in a cliff or enter the water if not node connection passes there - just make its position lerp from one nodes position to another.

Sorry for the rushed answer, don’t have much time - if you need help feel free to ask.

I didn’t realize NavMesh Layers was now free in Unity. I used it and found it to be exactly what I required. Check it out here. Kindly note that the docs dont seem to have been updated, and still show that it is only available in the Pro version of Unity.