The IP address you gave does not sound right - it is close to the IP address a workstation refers to itself - 127.0.0.1.
When you give a location A=300, do you mean that you have 300 hosts/workstations at that location?
Each location would need to have a public IP address, allocated by the ISP servicing the location. You need to make sure these IP addresses are fixed, not dynamic, so that the routers can refer to each location.
At each location a router will need to be set up. Inside the LAN, the hosts/workstations can use DHCP to get an IP address assigned by the local router. Alternatively, you can use a Class C subnet address like 10.0.0.x or 192.168.0.x where x has to be unique inside the subnet, 1 - 254. Your default gateway may be 192.168.0.1 and point to the router.
There is plenty of material on the net regarding subnets and also about designing the WAN and firewalling each LAN. The router configuration will require CCNA skills, though.