How to find the feature regions where each label is the most expected when using decision trees?
It seems that you want to achieve something like this :

Where you can see the instances, classes and the predicted and the cutoffs for the rules. The exemple is taken from : https://jakevdp.github.io/PythonDataScienceHandbook/05.08-random-forests.html You might want to find one that is interactive (plotly ?) so you can get the rules that interest you by hoovering your mouse above the graph.
Note that this appraoch has some problems :

It only work with two variables at a time. You migth need to plot similar graphs for all your couple of features.
It only work for simple classification trees. It might start to get more difficult to interpret the plots and the rules if your output is continuous.