As you know DRS using VMotion to balance the load across ESX hosts. VMotion is not supported on anything less than 1Gb link - it assumes a LAN connection between the hosts. So the first question is how much bandwidth have you got between your sites ?
Second you mention different networks. If a VM is vMotioned to a secondary site it will expect to find the same ipaddess range at the second site.
Have a a look at VMware Site Recovery Manager. It seems closer to your requirements than DRS for this particular task.