I'm running a wireless bridge using WZR-HP-G450H routers that shoots about a mile using 19 dbi panel antennas. I have it configured using the DD-WRT firmware. What I'm doing with this bridge is getting my internet from Comcast and sending it to my place of business that is located too far from the road.
It is configured mostly the same as described above. Differences being that I have the WAN setting set to "automatic configuration -DHCP". The problem that I am experiencing is that my WAN signal just drops for about 5 to 10 minutes then just comes back. The bridge is still intact. I can ping all the way into my Comcast router in 7 milliseconds constantly, I can even log into that and every other router in the chain but not receive the WAN signal. Looking at your recommendations above I noticed that you uncheck many of the firewall settings as well as a few other settings that I had not. I've made those changes now and we will see what happens. Do you think that this may effect it?