Heathlings not being able to reach or stuck

I tell my Hearthlings to mine I big section, but they aren’t smart enough in the order in wich they mine so they either get stuck or can’t reach a section because they mined everything beneath first. I feel that Hearthlings should be able to build their own ladders at will to reach.
there is a floating piece of stone they can’t reach so they build a latter to get to it then immediately take it down when they are done.
especially now that ladders are free.