I try meanwhile for two weeks to successfully connect AND ping and connect to Server in the subnet 192.168.50 or .55 (behind the 2nd Linux-Router). The VPN-Tunnel is established also (afaik), but nothing else happens. I can't reach on server. no Server in DMZ and no server in the inner-LAN behind the second Linux-Router. Also There are no logged drops or rejects from the firewall.
Maybe the answers is simple. According to your logs and your description everything seems to work fine. In the docs of freeswan you can read, that you CAN NOT ping into the VPN or to the other VPN-gateway from the gateway-box itself as long as you dont take connection type tunnel! So try to ping from a box in the VPN-subnet to a box in the other subnet. Yours Michael