The phone line itself is quite long, I'm at the end of the row of townhouses, so it's at least 100', plus internally there's a 25' or so cord looped there from the installer.
Whatever the case is, replacing the wiring in the electrical/telco room seems to have worked:
System Up Time: 2d, 1h, 17m
DSL Link Up Time: 2d, 1h, 16m
I'll probably spot check it from time to time, but I believe it to be finished. Hopefully everything I've posted in here will be Google'd for years to come by others who encounter hungry rats feasting on their phone lines, and save themselves some time