Rivnuts from Homestead, PA on 8/11/2021 1:14:38 PM:
I, myself, do not have first hand, current information to respond directly to your question.
However, as you know, this has been a recurring question since the National Park Service (NPS) announced the construction project along the towpath downriver from the tunnel. Originally the NPS C&O website stated that the towpath at the downriver exit would be closed from November of 2020 until the spring of 2022 and that riders would have to take the tunnel bypass trail.
However, forum contributors have consistently reported that the tunnel exit is not restricted and have not had to take the detour. That said, the NPS C&O website now states that the towpath "construction in that area is estimated to begin the week of August 9, 2021 and extend into the summer of 2022..."
With that statement, it will be important to obtain current feedback from travellers this week and thereafter as we move into the fall.
Its unfortunate that the NPS cannot simply provide a consistent and current status of that project to guide travellers in their planning.