I will tell you my experience removing old Paint- Stain .
I once had to deal with a railing where we need to get rid of alll existent paint, We Sand blasted It and It worked out as planned! You need to protect rest of surfaces with a vinyl - plastic film and get a bunch of those protetective glases.
There is another tool that I love and It 's called the power brush..
Great to remove old stain or cleaning up wood pillars,etc.
The wire brush is an accesory quite expensive but worth the $ 150 then you will need the a 1- 2 - 3 speed ( sort of grinder)
This kind of jobs are time consumming and if someone want to go after them you need to charge for that labor. As far quimical stripper they might work if paint is pelling already , other wise you need to apply one time and another.