Bob Engelhardt writes:

Joe Pfeiffer wrote:
... So, before I get
myself in trouble, how did they likely wire it?

Most likely the feeder with hot & neutral went to the light fixture
junction box. The neutral was wired to the fixture and the hot went
out to the switch. The switched hot back from the switch was wired to
the fixture. Very common.

H --------/\------------
S
N ------- L ----------

Ah, got it. Makes perfect sense, and given the relative locations of
the light, the switch, and the panel would have involved less wire.
Sucks for me, though. No outlets anywhere near to pull neutral from to
get it that way.

Hmmm... I see how to wire the switches now (certainly not how I wanted
to do it -- if I want to avoid digging holes in and then patching
wallboard, I'll have to run hot and neutral from the fixture to where
the existing switch is, put a switch there to act as a remote control,
and then put a switch up in the light fixture controlled by the switch
in the wall).

Thanks!
--
As we enjoy great advantages from the inventions of others, we should
be glad of an opportunity to serve others by any invention of ours;
and this we should do freely and generously. (Benjamin Franklin)