I can't find the circuit breakers for any of the upstair bedrooms in
this old, 1908 built house. Would it be reasonably safe to replace a
light switch wearing rubber gloves and rubber-soled shoes if it comes
down to having nno other options?

Ron

No. Do you have a death wish? Look harder for the breakers/fuses. If
next you're going to say there arean't any, then get the hell out of
that house and fast!