You can edit your posts in a local copy of your HubPress repository and then git push to your blog repo.

You will need to log onto HubPress Admin to publish your post because there is no command-line or API for HubPress that would allow you to publish any other way.

If you want a near WYSIWYG interface to edit your AsciiDoc files, applications like Atom Editor or AsciidocFX Editor are excellent choices.