I have a G3100 router and I want to know if I can add a second router to configure a VPN. I would be setting up a VPN so I can remote in to other computers at the house when I am not home. I have a Dell SOHO Sonicwall with the VPN capabilites that I can use. Is this possible with the G3100?
It's possible, but the key question is, do you have FiOS TV, or just Internet? If you have just Internet, you can take the G3100 out of the mix and just connect your own router directly to the ONT's Ethernet port. Getting an IP just requires performing a DHCP Release of your WAN IP before you turn off the G3100, and use DHCP to the ONT once the SonicWall is hooked up.
Otherwise, an alternative would be to port forward in the G3100, the required ports for your VPN to work to the SonicWall's "Outer" interface hosting your VPN. Your "Inner" interface will be a connection back to your home network. The SonicWall will dish out IP addresses only to the VPN, from another subnet (192.168.2.0/24 for example).