Going all the way to the pacific, I think it would depend on your distance per day and how cold you like to ride in as to if it is too late to start. I don't know about the weather along the route in the west.
As for the detour from Niagara Falls - Buffalo.
As you come down Upper Mountain Rd, you will turn Right at Military Rd, (there is a traffic light here) just before the on ramp to Canada at the Lewiston Queenston Bridge. There will be a large hospital on the far right corner. Take this road to the end, it will have a golf course on both sides. At the end of the road turn Left onto Lewiston Rd (rt 104). Take Lewiston road and keep bearing right, first at the school, and then across from the Niagara Falls Library, this road will turn into Main Street in Niagara Falls and will take you right towards the Rainbow bridge to Canada. Turn left just before the toll booths at the bridge onto Rainbow Blvd. If you want to visit the Maid of the mist or the American falls turn left at Old Falls Street or continue to the roundabout and take the first right onto 1st street. On the left side of First street just before the bridge to Goat Island there is a paved path that goes closer to the river. take this path and keep the river on your right. If you visit the park you can follow various paths keeping the river on your right.
Take this path to the end, it will end at Buffalo Ave after you go under the I-190 bridges to Grand Island. At the end of the path turn right onto Buffalo Ave. Take Buffalo Ave until a 4 way stop just before it goes under the Lasalle Expressway bridges. Turn Right, the road name stays the same(Buffalo Ave), There is a short bike path on the far side, but ends before the next main intersection. The road name changes from Buffalo Ave to River Road at the next light(Williams Rd), stay on River Road. At the start of Gratwick park there appears a bike path on the right, take this path thru the park and along River Road. When you see the KeyBank on the right at Goundry St the path will seperate from a sidewalk just before a bridge. Either take the sidewalk road over this bridge over Tonawanda Creek. At the end of the bridge before the intersection, a path will join the sidewalk, take the path down hill and turn left at the end, (you will almost turn around to get on the path) This is the Riverwalk path. Take this path until it ends in Buffalo near Hamilton St, it does extend to a bridge over I190 but sometimes the gates to the bridge are locked. Turn left on Hamilton St, then Right on Niagara St.
You can take the rotating train bridge over to Unity Island then take the draw bridge back or stay with Niagara St. Bear right with Niagara Street after going under a railroad bridge. The unity island option rejoins at Ferry St. Niagara St going left at Busti ave. Stay right and take the right sidewalk as it turns into a bike path going under the Peace bridge and then over the I-190, ending at Porter Ave. I believe the current ACA NT route and the UGRR joins here just after crossing the peace bridge. Turn Right at Porter Ave, a bike path is on the right.
Note Google maps is still routing bikes along non roads that haven't existed in 3 years from the Lewiston Queenston Bridge to the Rainbow Bridge. Also there is a signed bicycle detour in the same area (going the opposite direction) that sends bicyclist down a dead end street (for cyclists) as the connection to a path and the path has been blocked by several feet of dirt dumped on it for road constrution.
Jeff
