Xorg was configured automatically. The kernel driver i915 is loaded, and the xorg.conf can be seen below.
To enable the external monitor, two programs exist: i810switch and i855-CRT.
First I tried i810switch. This correctly detected the current state (LCD on, CRT off), but when I tried to switch on the CRT with the command “i810switch lcd on crt on” I got a very unsteady image on the CRT, and the utility reported “No LCD support for this chipset.”.
Next up was i855-CRT. Running “sudo i855CRT on 1024×768@85” enabled the external CRT. However, there was no cursor, and a white square at the top-left of the monitor. Next I tried “i855crt on rawpipe” which gave exactly the same result as i810switch did. Unsurprising, since this is the same method as i810switch uses. Last attempt was “i855crt swcursor on 1024×768@85”. which was almost right. The only thing lacking was a cursor, which is a bit of a bummer. So I took the time to actually read the README for the utility, which mentioned switching X to not use hardware cursor. Putting Option “SWCursor” “1” in the device section of xorg.conf did this, and lo and behold, it worked! It also mentioned that there is a patch for XFree86 to allow this to work for hardware cursor as well. Using this setting lowers performance, so I set it to 0 again, because I don’t anticipate using external CRT.