[morzh]

1. So you have two bad resistors, the rest within 20% after 90 years, and you want to change them all because you are afraid that in your lifetime they will get much, much worse?
Well, electrically there is nothing wrong with it. Is it a waste of effort? I think, yes. But it is your effort and your time.

2. I think it is a mistake in the chassis diagram. What they show as the resistor #68, which is the ONLY resistor that is connected to the cap C62, is supposed to be the #64, 9K resistor. There are no other resistors there.
Wereas #68 in the parts list is listed as the Wave Switch Antenna, which it is obviously not.
The big resistor next to the transformer, white with red dot is the 9K resistor.

3. All trimmer/padder caps (inside or outside RF transformers) stay, unless physically damaged or rusted beyond repair.

4. All backelite block caps are paper caps. All go.

5. Tone control: trace it, it is a simple circuit. One wire goes to R46-C47 connection point (right bottom in the chassis diagram, they go to that solder strip), another to C56-C57 conenction point (they are right over the power transformer). There should be nothing else othter than chassis connection which is likely done through bolting it to the chassis, but could possibly be a wire.

6. Stick to running the wires the way they have been routed. While mostly not important, there are cases where the wire was intentionally routed away form an offending signal to reduce hum or noise.