What you’re talking about is actually called “interpolate” in inkscape. It’s pretty well documented but it can sometimes introduce errors into your paths. I mean so can inset and outset which is why I like stroke to path… You just have to make sure your path is constrained enough.
You can interpolate between any two paths, from one shape to another or from one size of a shape to another size of a shape and it will make intermediate steps in between. It’s not going to be as precise unless you do some math to figure out how many steps you need to get the lines per inch that you are looking for.