The complexity level of the workbooks is going to need to be reviewed carefully. Open up the workbooks with the folks that designed them and walk through what was done. Try to reproduce the work already created and then take it a step further so you can use your own knowledge with them and take things a step further. Hopefully the data fields have also been well documented.
Are the data sources on Tableau Server or live connections?
under Security implementation - Understand the permission structure for Tableau Server. Who has what permissions and why? Tie the permissions to data access. Do they make sense?
This is a great question but I'm going to move it to the Server Administration area of the forums because there may be some other Administrators that would like to chime in.
Probably you want to know about their current Environments.
- How many environments (TEST, PROD)?
- One server per environment? One project per environment? One folder per environment?
- Who are the users for each environment?
- What's the process in migrating workbooks and data sources between environments?
- What are the configuration differences between environments?
- What custom configurations/codes were developed for each environment?
- What issues are there for each environment. I.e., performance issue?
- What are the current backup strategy for each environment?