Give a Windows 2008 VM Internet access but block Host LAN access?

Securing a guest VM to give it internet access, but block access to host LAN

The above was a similar question asked for Linux but the following has specifics that are different.

We need to have this VM (clone from a key server/ DC) Updated (via the Internet) to test something but not allow this clone to access the Host LAN & other machines.

The VM is Windows SBS 2008 and is on a Test Box running Win 2012 R2 with both: Hyper V and VMWare (being able to switch in between).

Currently it is inside VMWare Workstation 10.0 but we’ve also had a cloned one inside Hyper V as well.

So whichever way is easier to make this happen please do point out.