Re: Knob & tubing . rewiring?
K&T wiring is OK if undisturbed, however you will find few homes with K&T that the wiring has not been modified. Adding taps improperly, over fusing, and insulating are common items that can cause serious concerns. The wire insulation is no doubt dried out and brittle so any modification, including changing fixtures or outlets, can cause the wire insulation to break and fall off leaving bare wires.
At this stage, I would always consider rewire as the most viable option which would also allow for adding proper grounding and a service update.
Can it be don as a DIY project, yes and no, it depends on your skill level and knowledge of proper electrical procedures and code. Improperly done and your house burns down could lead to an insurance company rejecting your claim.
Be sure you live your life, because you are a long time dead.-Scottish Proverb