site b router
ip route 192.168.10.0 255.255.255.0 192.168.20.1(not sure if you need to reach this subnet)
ip route 192.168.17.0 255.255.255.0 192.168.20.1(not sure if you need to reach this subnet)
ip route 10.116.16.0 255.255.255.0 192.168.20.1 (DNS fileshare)
ip route 10.104.17.128 255.255.255.128 192.168.100.1
ip route 0.0.0.0 0.0.0.0 192.168.20.1 (you may only need this route)this will get you to the internet
router A
ip route 10.104.17.128 255.255.255.128 192.168.20.2(for remote lan segment)
ip route 192.168.100.0 255.255.255.0 192.168.20.2
ip route 0.0.0.0 0.0.0.0 192.168.17.9 (to the internet)
ip route 192.168.16.0 255.255.255.0 192.168.17.9
I think that cover them all