When I shoot up labs with FortiGate firewalls in my local environment, I usually connect port1 to the inside because it allows access (PING, HTTP(S), SSH, FMGR) by default; in other words all the other ports are protected with factory default settings.
One laptop can take down major internet servers - says the title of a recent article on Engadget. The article refers to TDC SOC, where the attack is described.
This article describes how to create VPN tunnels between a FortiGate firewall and Cisco routers using Virtual Tunnel Interfaces. OSPF is being used for routing. I used an unlicensed instance of FortiGate VM in GNS3 so you can recreate the setup without any financial investment.