This is where John D Clark's book "Ignition!" really shines: it's the history of the science of rocket fuel as problem solving. Plenty of candidates on paper, need to be tested for detonation, hypergolicity, ease of ignition, handling, effect on plumbing etc. Red fuming nitric acid is a good example: great oxidiser, doesn't need cryogenics but is liquid even in arctic temperatures. Only problem is it eats through the tanks, until they discovered that adding a small quantity of HF made it OK to store in stainless steel.

I suspect that he would have taken one look at handling radioactive corrosive liquid at 600C and asked to go back to the nice safe rocket lab with only a few explosions.