Which configuration scenario would be best for this

DinoRS

So I have the following plan:

I have a windows Server (Srv01) in a datacenter. I want to run the OpenVPN Server on that machine.
I have multiple routers at different locations (RT01 - RT05) with LAN-Networks behind, the routers should act as VPN Clients to give access to the LAN behind and all other networks and devices
and last but not least I have Smartcards for Clients outside either router location.

I'll be running an Active Directory Service behind one router. I want this Active Directory Service to provide functionality for Srv01 so Exchange can run there.
I'd like to be able to use all Windows features (Network Discovery and so on) on all the machines wether they're behind a router location, connecting through a Smartcard or being the Windows Server in the Datacenter.

What kind of setup would you suggest to me? Which one can fullfill these requirements for all participants properly?

Mimiko

Network Discovery and so on

For this you have to use bridged setup. But it is not recommended as the tunnel will be filled up with lots of traffic. So or you enable Network Discovery and face the slow connection, or don't use Network Discovery and have a good fast connection.

DinoRS

Well I am kind of concerned towards Active Directory if I would leave out Network Discovery. I wouldn't mind a slow connection that much really I'm only having heavy traffic behind the routers on the LAN, the VPN shall just provide basic ability to manage computers and maybe transfer a few documents between locations and ofcourse auth the exchange server.

I'm even considering for Smartcard Users only being allowed to get to the Machine on the Datacenter, in theory I can use that machine to manage any broken computers on the sites?