Actually, I got it working! I emailed the goCoax Team and they got real quick to me with the solution: what I neglected to do was hookup my second goCoax to my Router. Essentially I have a Home Network looking like this now:
OPT --Ethernet--> Router --Ethernet--> goCoax1 --Coax--> [Coax Wiring Going Throughout Home] --Coax--> goCoax2 --Ethernet--> PC
I look to be getting the expected speeds I would expect to get from:
OPT --Ethernet--> Router --Ethernet--> PC
Still having trouble getting into the MoCA Admin, even after resetting the goCoax devices though, so that stinks if I ever need to use Static IPs.