RE: HOW TO HANDLE THE SETUP FOR TWO COMPANIES IN DIFFERENT STATES
Thanks Pat for clarification,
I understand what your goal is, but IMHO it would be wiser to upgrade your GP first, because then you would also get the most recent tools to do the data transition from your legacy AS400 system... every time you upgrade a major GP version, you get the benefits of the Integration Manager with GP for a 6-months period for free.. (unless you're out of support with Microsoft).
You may not want to go to the latest GP release, but I'd at least go the last supported mainstream version, which is GP2013R2. It will also be easier to get support if you run into troubles with a (almost) current version of GP.