I have been using the Hershey-extension that comes with Inkscape. As far as I understand the Hershey fonts are defined using straight-line vectors only. I wanted to have a truly rounded version of the script 1 stroke font and used the Hershey-extension to build the glyphs. Then I edited the nodes to get smooth paths. See the difference in the image below. I also added some letters for being able to write Norwegian letters. Then I took the paths through this process to create a singe line True Type font.
Here I have tested the resulting font in Inkscape using this process to reopen the closed paths of the True Type font.