I think you might be on the right trail, at least for 1 solution, using the stroke. Actually, using the stroke is how to avoid the rounding that can occur with....perhaps, arguably, the correct solution, which is path offsets (Path menu > Inset, Outset, etc.) So I'm not sure what you mean about the stroke making it rounded.
Before I make an example/tutorial for you, is the font you used free? Can you give me a link to download it? Otherwise I'll use something similar.