It sounds like your use case is similar to something I'm working on.

While I like the STEEMPRESS plugin, it seems geared for a bit of a different posting workflow. I've forked it and have made some modifications to fit better with what I'm doing.

You can find my fork at http://wordpress.org/plugins/another-steempress - it just might be a better fit for your use case. If you have thoughts or suggestions, I'd be happy to think about them.

Also, because I sincerely appreciate the work done by the Steempress team, posts made through AnotherSteempress also send rewards to the Steempress project.

Anyway - best of luck to you!