Office 365/Active Directory Synchronisation

Good Morning,

For the past 12 months we have been running Office365 in our organisation for email and using DIRSync to synchronise our Active Directory accounts to the cloud.

This has been working well, however we would like to move from On Premise SharePoint Foundation 2013 to SharePoint Online.

I am asking the experts here on the best options for allowing users access SharePoint Online and other Office 365 applications when connected to the domain without having to re enter credentials.

I have briefly looked at Centrify and I am unwilling to take the Active Directory Federated Services route as we don't really want to add another layer of hardware to our infrastructure, I am the only support person for our organisation and I need to keep things simple as possible for those rare times when I am unavailable.

Thanks in advance,

Gerald Meyer