These walks all require a net gain in elevation.
To have a net loss in elevation start at:
Mt Victoria 7:00 hours
Blackheath 5:30 hours
Medlow Bath 4.30 hours
Katoomba 3.00 hours
Leura 1:30 hours
While the walks generally follow the highway there are many side tracks available avoiding the noisy traffic. (Just like the Camino.) While you may need to cross the highway in several places there is no need to ever walk unprotected on the highway itself.