Blackheathens and other interested residents have until November 14 to tell Transport for NSW which tunnel option they favour.
TfNSW recently removed the two western options which would have meant compulsory acquisition of multiple homes and businesses.
The transport body is now seeking views about whether to go for a short or a long tunnel. (See nswroads.work/greatwesternhighway.)
Both options would see the western end emerge near the heavy vehicle weigh station. Towards the east, a portal would be either near Evans Lookout Road (long tunnel) or Sutton Park rest area (short option). The short tunnel would impact 12 nearby properties.
Meanwhile, doubts linger over whether the option to duplicate the highway through the middle of town is really off the agenda.
When regional transport and roads minister, Paul Toole, trumpeted the removal of the two western routes earlier this month, he did not mention the option which would involve widening the existing highway.
The Gazette asked TfNSW western director, Alistair Lunn, whether it, too, had been abandoned.
His answer was: "As a tunnel has been selected as the best option for the highway upgrade through Blackheath and endorsed by the community, duplication of the existing highway through Blackheath is no longer being actively progressed by Transport for NSW."
At an online consultation last week, the question was answered with: "Off the table, at present."
After a second consultation, one resident concluded that TfNSW "categorically confirmed the widening option has been dropped" but another posted online: "Didn't sound like a categorical denial to me."
Local resident Gary Moore said he has asked Mr Toole and TfNSW to publicly state that the through town option is off the agenda.
"As it stands, if the tunnel options don't stack up in terms of geotechnical barriers, underground and above ground environmental damage, property and public domain damage and cost and lack of budget, then through town becomes the favoured option," Mr Moore said.