I wouldn't change anything that doesn't need to be.
Its a false economy. 95 % of the new stuff isn't made as well as the old stuff.
If it has a soft wall or leak, that's anothe story.
Hard line the whole way. Steel or stainless steel. Cooler, stronger, lowest friction.
It's generally pretty well protected the way the factory ran it. I can't think of any location that got armor (coil).
Frame in the engine bay can sometimes be a bit close to headers (that's an issue on my 67 but no one else has those headers)