Suggest Virtualization scenario for Windows Server 2012

I've inherited a server running windows 2003 server enterprise, with a domain setup, but over the years, all the clients and replacement clients stopped using domain authentication and just use simple file share.

8 local w10 clients access a simple shared folder of scans on the server.
3 local w10 clients login to the server using TS to access quickbooks, a title companny application (magram TACS), and redvision
4 remote clients login to the server using TS to access a title companny application (magram TACS), and redvision

We need to replace the server with newer hardware, bring all the clients into AD for security and group policy management, and lock everything down. A few more clients will be using TS to access applications on the server in the near future.

I've had little experience with virtualization besides experimentation.

Looking at Windows Server 2012 R2 Standard, it has 2 vm's initially available on teh base license

I am curious as to how people normally virtualize small setups like ours, or theirs, basically, the question is, virtualize what, and keep what on the physical server?

Keep the physical server as the domain controller, then run 1 hyper-v VM to server for RDS access to apps/file server?

Or run the DC in one VM, and RDS/file server in another VM?

What about running a secondary DC on a retired box?