> How would the lorry know that it can reach it?

It knows the network, the network knows what's connected. So it's just a pathfinding thing. Of course, with no network but the landscape this is impossible.

> Elaborate.

It sounds good as long as you only have one storage where you produce your stuff. But what about two buildings requiring say...wood. (workshop and foundry or whatever). Which building to supply? And what if you want to alter it? This should be an easy task but will outcome as shifting your whole transportation route, with great effort in forming the landscape.

> Assuming, of course, that rails are stable enough to survive meteors or equipped Clonks. Does that mean you plan rails to be invulnerable and permanent? If not, how do you decide who's able to deconstruct them?

Yeah, here's still some thinking to do. But I would strongly favour rails more tough than getting destroyed by one little hit.