I finally got around to testing the last 2 WiFi Bridge boards. Neither worked at first. I wasn't sure of anything.
I chose one board and went through the entire regression. When I finally got the scope (Xprotolab) out and followed the NMEA signal in, I found a broken trace. The input to the first resistor. Arg! Then I discovered I put the transistor in backwards in both boards.
But now they are both installed and broadcasting. The first is connected to the builtin Garmin GPS and depth finder data, wire-or'd on the same terminal strip at 4800 baud. And the second is connected to the AIS at 38400 baud.
Then I etched two more boards, but haven't drilled or populated them yet.