I sent a message to the National Park Service asking about the work on the bridge. As I understand it the south sidewalk is to receive some “bridges” similar to what are now installed on the north sidewalk to cover deteriorated sidewalk areas. The closure is only expected to take another week or so.
The middle section of the trail along Route 110 is pretty clear, however, both ends are covered in ice and packed snow. We use it and walk the bike on the bad parts.