Sorry for disappearing! The router from eBay finally arrived. I flashed the firmware to version 2.5.1.16, reset it to factory defaults, enabled the telnet option from the debug page, and proceeded to run most of the commands listed here (I'll make a series of posts with the output of each command).
Also, when trying to dump the firmware image using binwalk -Me, I received a message about symlinks being removed for security reasons. Does that affect anything?