Making folders when the names have "/" and " ' "

I'm building up file paths (and mkdir-ing them) based on variables:

mkdir "$root_folder/$title ($year)"

I came across a situation where $title was 9/11: Inside the President's War Room. The / is a problem because mkdir will interpret it as a folder path. So I want to replace all / with \/ so that mkdir takes it literally instead of thinking it's a path. The ' in the name is also giving problems. So I also want to replace all ' with \' but this is harder than I thought.

My end goal is to just make the folders in such way that those / and ' are literally interpreted. Some things I've already tried:

title=$(echo "$title" | sed -e "s|'|$(echo "\\")\'|g")
${title/\//\\/}
#---
title=$(echo "$title" | sed -e "s|'|$(echo "\\")\'|g" -e "s|/|\\/|g")
$title
#---
mkdir "$root_folder/'$title ($year)'"

Single or double quotes will not cause any problems as long as you keep the variables properly quoted at all times.

$ title=$(cat << END_TITLE
This "is a title" with 'two kinds of quotes'
END_TITLE
)

$ declare -p title
declare -- title="This \"is a title\" with 'two kinds of quotes'"

$ mkdir "$title"      # no need to try to force extra quotes in here

$ echo $?
0

filenames may not contain a / character, no matter how hard you try to escape it. Slash is the directory separator. You'll have to substitute a different character. Suppose you choose -:

mkdir "$root_folder/${title//\//-} ($year)"

That uses bash's Shell Parameter Expansion instead of calling out to sed.