I see the new 800 series offers failover and load balancing with the 2 WAN ports. Is this also possible with VPN? Could 2 tunnels be created between 2 RF860 routers giving fail over and load balancing within the VPN tunnel?

You must be running 3.31 and above in order for VPN failover to work.

Here is a link to our "howto-vpn-failover.txt" document.