afaik you can’t mount folders, only drives. So what you’re looking for are symlinks (symbolic links, as opposed to hard links; use e.g. ln -s <source> ~/Downloads). I have a few in my $HOME pointing to other drives as well.
if your NTFS drive is unmounted or unavailable, the link will be broken; but you won’t have to recreate it in the future: so it’s a “set and forget” operation for as long as the path the link points to remains the same.