I'd like to introduce you an interesting PPM Partner solution that will help you copy your on-premises data from Project Server 2010 to your Project Preview tenant.
The solution is called FluentPro Cloud Migrator Pro and it's designed to migrate data and configuration from Microsoft Project Server 2010 to Project Online. FluentPro Cloud Migrator Pro migrates entire configuration (Custom Fields / Lookups / EPT / PDP / Views / Settings / Portfolio Analysis / Security), Resources and project schedules with values in all custom fields (project level as well as task level). Suite contains 3 packages: FluentPro Cloud Migrator for configuration migration and 2 add-ons for Project Professional (v. 2010 and v. 2013)
Anton Kravtsov, FluentPro co-founder: "Moving solutions to the cloud is now a very vital option for globally distributed organizations – this allows organizations to get more scalable, global and modern platform without compromising stability or security, save on maintenance and administration, get better uptime for the EPM system from Microsoft and pay just for consumer resources on monthly basis. To make it easier to upgrade your full data and settings to Project Online - FluentPro Cloud Migrator Pro helps organizations to move their configurations and data in an automated way. In additions to the software suite, FluentPro provides support and assistance for migration process for customers and offers the managed migration services."
For any questions or support queries, please follow-up directly with FluentPro.