Just to add a detail regarding the VPN setup between the main office and the remote locations...you don't have to have a static IP address at any of the locations. There are several free dynamic DNS services that routers support any many routers (we use Netgear) allow you to use DNS for the VPN rather than an IP address. We do that with our office setup where one location does not have a static IP address so we use a dynamic DNS name to keep the VPN working. You never have to update the IP address.