Linksys Wireless Router :: E4200 - Running In Bridge Mode /Automatic DHCP?

I am trying to determine the best way to setup my E4200 V2 so that it is “uplinked” correctly to a Comcast Dory Modem/router.  Currently we have the E4200 V2 router plugged into the Comcast Dory Modem/Router using a CAT6 cable from one of the Ethernet ports on the Comcast device to the WAN port on the E4200.  The E4200 is set to “Automatic Configuration - DHCP.”  
 
We are trying to do two things.  First better WIFI in the center of the house and for a TV located next to the Comcast device, and second, have all devices in this house see and access all other devices including the Samsung SmartTV, my son’s two systems upstairs, the 3 systems in the room with the E4200, and the one network printer.  In the room with the E4200 we have 3 computers and one network printer.  3 of those 4 devices support WIFI so we don’t have to use all 4 Ethernet ports on the E4200.     
 
I see others talking about running the CAT6 cable to an Ethernet port on the E4200 instead of the WAN port and setting it to “Bridge Mode.”  Right now the system appears to be working fine although we are sometimes experiencing brief dropped connections with the devices hardwired into the E4200. 
 
Should I be running the E4200 in “Bridge” mode or “Automatic DHCP” mode and which port on E4200 should the CAT6 from Comcast be plugged into?