Update: Moderate success.

I've got the EC2 instance connected to my local network via OpenVPN. I can ping the EC2 instance via the VPN and the EC2 instance can ping my Poser Workstation.

By the way I owe you all a huge thanks for your support and contributions, millighost in particular gave me a key piece of information about making sure the VPN IP's were on the same IP range (subnet?) as my LAN addresses and to look at ethernet bridging.

Now here's the "moderate" part of my success thus far: The EC2 Queue Manager picks up the job posted by the workstation (great!) but the objects it has to transport up to the EC2 instance seem to be taking quite a while and this is not a complex scene. 

I looked at the connection on the EC2 instance and it says it's a 10Mbps VPN connection, and in reality my upload rate with my ISP is only ~2.5MBps (which I guess equates to 20Mbps).

However it's only reporting ~5% usage of the 10Mbps link so that's a little suspicious to me. Maybe it's just because I'm running the Free Tier and Amazon is throttling even that bandwidth. I'll look into that.

Complaints about upload speed, however, are a familiar line from the people I talk to about the Cloud. The ISP upload speed is now the bottle neck for this project. I'm gonna talk to my ISP about this to see what options I have available to me, but at this point this has more to do with AWS/ISP file transfer efficiency than with Poser/QM.

Queue Manager is up in the cloud and taking jobs. The next step is to find out how efficient one of the Cluster GPU instances at rendering scenes, but that'll have to wait until I resolve the data transfer issue because I'm not gonna spin up an hour of time on a Cluster GPU AMI for 59 minutes of file transfer and 1 minute of rendering :)

I'll post again with more updates (and possibly a guide to this point when I get a chance to write one out).