Re: Painting treated pine porch railing
Use re-dried pressure treated material. Or use better exterior wood that is not PT. Porch rails normally don't see weather like deck rails, since presumably they are under roof. Back priming regular millwork stock (generally it's fir in my area) and priming the end grain of all your cuts is enough to ensure a long lasting rail detail. Using SS fasteners is also a plus. If your wallet will tolerate it, you can use spanish cedar or mahogany for exterior railing and paint or leave it unpainted.
Remove not the ancient landmark, which your fathers have set.