I would recommend that you start by taking a look at the following Apple Support article on roaming networks.
The key to success of any "advanced" network is to start from scratch. I would recommend that you perform a "factory default" reset on each of your base stations, and then, use the AirPort Utility to configure them.
Power off the Porch Express for now.
With the Living Room AirPort Express powered on for a few minutes, hold in the reset button on the back of the device for 9-10 seconds and release. Allow a full minute for the AirPort Express to restart to a slow, blinking amber light.
Connect the Ethernet cable from a LAN <-> port on the Time Capsule to the WAN "O" port on the LR Express.
Click the AirPort icon at the top of the Mac's screen and wait a few seconds for a listing of New AirPort Base Station to appear. Just below that, click directly on AirPort Express.
AirPort Setup will open up automatically and take a minute to analyze the network, then announce that the Express will be configured to extend the Time Capsule network.
Enter a device name that you want to use.......LRExpress.....for example, and click Next
Now the screen will indicate that the Express is being configured to extend using Ethernet. When you see the message of Setup Complete, click Done. That''s it.
Use the same procedure for the Porch Express.