Martha, terminology here is unclear to me.
First off, while your idea for a "pre-packaged, free workbook" is a good one, it requires some version of Tableau Desktop if you want users to be able to make any modifications to the content.
Creator and Explorer, the way you are using them, only applies to access to a Tableau Server. If you want people to be able to open, edit, and save workbooks, then you only have one option and that's Tableau Desktop. That comes in 2 (major) flavors: Tableau Public (which only allows you to SAVE to Tableau Public) and the full product that also comes with a Creator license for access to a Tableau Server instance (Server or Online).
Short of the 15-day trial, there is no way to give individuals with no server access a way to create, edit and save workbooks without them having a copy of Tableau Desktop.
For users that you intend to give an Explorer license to, the only way for THEM to create content is actually on Tableau Server itself. There is no Desktop component to the Explorer license.
So, for the users you intend to have Creator licenses ON TABLEAU SERVER, you already have Tableau Desktop available for them to use. You don't have to connect them to Server right away if you don't want to: they can do everything on a local machine. Tableau Desktop ships with several sample workbooks, or someone in your organization can create a workbook with your data for your users to use. Server doesn't need to enter the picture at all for those users until you have determined that they are ready for it.
For Explorer users, there's not much you can do other than the 15-day license. I would suggest talking to your Tableau Salesperson to see if a longer trial license might be an option for those folks.
Thank you so much for your answer. I understand your comments. They definitely provide clarity to my situation. Thank you also for your suggestion on asking Tableau Salesperson for a longer trial license!
I was wondering also about the potential of our customers using Tableau Reader to interact with our visualizations (and pre-prepared non-live data set) without having any license assigned. While we understand there's no mechanism for them to create or modify workbooks without a license, we'd like them to experience the workbooks as a consumer without committing a license to them.
Any feedback from your experience on this?