It's the missing link for cyclists - the stretch between Katoomba and Medlow Bath has long been the only part of the entire Mountains where the highway can't be avoided.
But recent work by council, creating a path from the Explorers Tree to Medlow, will shortly fill in that gap.
One man delighted with the development is retired geologist, Brian Stevens from Springwood, who has spent hours riding from Emu Plains to Little Hartley to find tracks that take cyclists the entire journey without stepping on to the highway.
He has used service roads, back streets and bits of the old highway to create a crossing map suitable for mountain, BMX or hybrid bikes.
The result is a little book published last week Cycle Across the Blue Mountains Without Using the Highway.
It's a book for "the people who want to ride through the Blue Mountains towns with the options of stopping off at coffee shops, cafes or pubs, and with the option of catching the train if it all gets too hard," he said.
Testing part of the new Medlow-Katoomba stretch last week he declared it a winner.
"This is a really awful stretch of road for cyclists," he said, looking at the tiny shoulder of road just centimetres from passing trucks.
"But this," he said, looking at the new dirt track, "is beautiful. The only thing is the gradient's nowhere near as good as the road, but I'm not going to complain because I know they only had a half-million-dollar grant. And it's a helluva lot better than what was there."
The 67-year-old returned to the Mountains after 30 years living in Broken Hill and embarked on his project to find how to get around without the highway.
"There are places where I cheat a bit and use the footpath, but there aren't usually any pedestrians around. I figure I would rather get fined than flattened by a truck."
He said Linden offered no alternative except a footpath, but he had only ever seen one pedestrian there, unlike at Hazelbrook, where there is a shared footpath but "there are always pedestrians there".
Another hairy spot is the back road from Wentworth Falls through Bullaburra to Lawson, which is very narrow. And he offers two routes from Leura to Katoomba one for the "masochists" which includes the Lovel Street hill, and one for "normal people".
A council spokeswoman said this section of the Great Blue Mountains trail, which will extend from Katoomba to Blackheath, will comprise 3.2km of shared trail (varying from stabilised gravel, asphalt and concrete) and 10km of unsealed path. It is being funded by a grant of $500,000 from the previous Labor federal government plus funding for 10 work for the dole participants and should be completed by March next year.
Mr Stevens' book is available for $15 from the Turning Page bookshop in Springwood, from Panther Cycles and from Dymocks, both in Penrith, or email him on barney.stevens@westnet.com.au and he will post a copy.