@tekbird 

What you need is Policy Routing. I have tested with the Policy Routing on TP-LINK router and it works like a charm. I ran into the issue with the dual WAN and not giving me the right WAN IP when load balancing. I believe you use some kind of whatsmyip? Don't use that. That kind of website sucks. Try the tracert command instead of trash websites. Tracert can give you the most accurate result. 

https://www.tp-link.com/us/support/faq/2134/

BTW, do you use VPN? ER605 is the VPN client? What kind of VPN do you use? 

I have the L2TP VPN server, and a PPTP client configured in the TP-LINK. what I want is to forward packets coming from L2TP clients to the PPTP tunnel, is that possible? I tried using policy routing after enabling the load balancing. and I don't see any change in the routing table and the packets were still routed through a wan IP. I want the IP to be the one that where the PPTP server runs. Also, at times I want to route LT2P client packets to one of the WANs

at the worst, i should be able to selectively route packets to one of the WANs, I am not looking for load balacing, I want to use any one WAN at a time. Right now the WAN2 automatically takes precedence and I dont get an option to change the routing to WAN2

@tekbird 

The routing table is about Static Routing.

Supposedly, you should use static routing instead of policy routing. 

Also, at times I want to route LT2P client packets to one of the WANs

L2TP client you set on the ER605 is using a WAN to establish the VPN tunnel. Do you want to get Internet by proxy? NAT mode is the right mode for you.

If you use a PC to connect the L2TP server, you set the proxy on your windows(other OS) PC. 

To get Internet by proxy, you use direct connection. Router won't proxy for you. 

https://www.tp-link.com/en/support/faq/2137/