According to a native japanese, semai sounds almost childish here. She would use hosomichi for narrow path.
According to this link: https://oshiete.goo.ne.jp/qa/8122767.html
While we call a narrow path "細道（ほそみち）," if the road looks narrow in a 3D way (e.g. with tall trees or walls in both sides limiting the view) it would be called 狭い道（せまいみち）.
Is this "path" as in a litteral road, or like "the path of the righteous" type thing
I think both
It can mean both (though I thin the literal interpretation is more common).
Both. It even means "Dao" (well, it IS dao). On-yomi of the kanji is "do:", so you also use it in, for example, "karatedo:", or even "suido:"(which means "water supply").
So path and street is みち？
Why not 「道路」？
I would translate 道路 to road rather than path.