Moving all objects in AD across domains in separate forests

Hi,

I have two seperate, disparate AD single-domain forests. Completely different networks, but public (a vpn and firewall is going to be put in place!).

I want to move all the objects in one domain (not just users, but OUs, and other things too) to the other domain. What's the best option to do this.

I believe creating a trust is one such option? But this may be a bit complex?

As both forests use Windows Server 2012, Powershell is an option.

Thanks