I finally got around to assembling the PCB's sent out to Dirty PCB's and OSH Park, and there were a few small errors on the original design. The ESP8266-201 breakout module has 10k pull-down resistors on at least the GPIO0 and GPIO2 pins, so when I tried to boot the chip, the pins were left floating (I'd used 10k resistors to pull down the pins, same as the ones on the 201). Additionally, the resistor between the dip switches and 3.3v is too big - it should be much smaller than the pull-down resistors so that when the switches are turned on, the pin goes high instead of low. The pull-downs were reduced to 1k, and the other resistor was replaced with a jumper. In the next revision, I'll just have the switches connect the pins to ground when closed instead of pulling the pins down and connecting them to 3.3v when closed.

The CH_EN pin had to be attached with a wire - I just put this on the bottom of the board. Fortunately, it doesn't protrude past the various through-hole components.

The one other awkward bit was attaching the USB micro connector: the OSH Park boards did not have the different shaped holes that were put in on KiCad, but the Dirty PCB's ones did. This means that to get the USB micro connectors to connect to the OSH Park boards, I had to trim the leads for the shielding because the slit-shaped holes on the design became small round ones.

Other than that, I've successfully managed to hook up the usb-uart adapter and flash over a test WiFi program.