Save/open from h5p 'documentation' .. or equivalent?

I’m looking for a tool to build things like worksheets into a PB book. The h5p documentation tool seems like it does a lot of what I want, but here are two I have with it:
*Users must finish the complete task and export, otherwise they will lose any partial work – i.e., it would be great if there were a save button with corresponding open that allowed users to leave and come back to that task.
*Too bad the only export file type is Word… I wish there were other options.

Final, related issue: what does this look like on export of the book itself? It would be nice if there were some canonical form of the worksheet which would appear in the export in a way that it could be filled out on paper…

Any ideas, folks? Thanks in advance!