Question : New domain, new subnet

Ok Experts, this should be an easy one.  Enterprise AD and Networking deffinately aren't my specialties.

We are planning on deploying several "sandbox environments" that are used for development purposes.  We would like to host these in their own AD forest and put them on a seperate subnet from our corporate LAN.  All of the environments are virtual (running on a single hyper-v host) and will be running Server 2008 (some R2).  

I'm not entirely sure about the best way to do this.  I planned on standing up a Server 2008 domain controller, creating a new forest (dev.corp.net), and putting them on 192.168.110.0 /24 subnet (our internal is 192.168.108.0 /23).  I would then create a one way trust between the dev forest and our internal forest (int.corp.net).  Sound ok so far?

How do I handle the routing between the subnets?  Would it be better to also stand up an RRAS server to do this, or should I use our hardware router (which has an empty port/interface)?  If I use the hardware router, do I need to take a dedicated cable from the empty port and connect it to the switch our host will be plugged into?  We have a router and two switches (connected via fibre), one switch has our office workstations and the other switch has our servers.  

Answer : New domain, new subnet

Why should you create trust between production and dev.
Create a independent AD forest for dev, use any of the hardware router to do the routing between dev - prod subnet. Create a gateway server (jump server, will used to access two different environemnt using either windows TS or CItrix). access to the dev should be restricted by either gateway or dev AD.