There is construction on the west bound (to Canada) entrance to the Lewiston Queenston bridge. It closes the ramp listed in the route. There is no listed bike detour, the signed detour puts you on the highway further back. Below is a bikable detour that takes you to the rainbow bridge.
At the light at Military Rd and Upper Mountain Rd, just before the bridge to Canada, make a right on Military rd. Take this to the end and make a left on Lewiston Rd rt 104. Take this past 2 lights, Niagara University will be on your left. Make a right into the onramp/parking lot for Devils Hole State Park. To the left you will see a pedistrian overpass over the highway, Cross the bridge and then keep the river to the right. Take this Path all the way to the end and then make a right to the Rainbow bridge. After the customs booths make a right on the first street and then make another right on Hiram St and rejoin the route by making a right on the Niagara Parkway.