Hi
@mikew - Welcome to the forum. This kind of question gets asked a lot. I am not an IBA official, but my understanding is that for End to End rides, like Coast To Coast rides, the intent is that you have to start your ride at the end points, not in the middle. It's an End to End ride, not a Middle to End to End to Middle ride.
The length of the 401 requires that you do traverse it twice to qualify for the SS1600 ride. From the rules for the 401 E2E, (I've added bold):
--you must ride the entire length of the 401
from before its beginning to after its end within the allotted time
and return
--You must traverse the end points and get DBRs in Riviere-Beaudette, Quebec and Windsor, Ontario
--
You must enter/exit the 401 from Highway 20 on the east end; and exit/enter the 401 to Ojibway Parkway in Windsor in the west.
--You must complete the ride in less than 24 hours
Full rule page
HERE
So you're going to need to ride to Windsor and get a DBR, and for clarity, start your tracking off the 401, then enter from
Ojibway Parkway. It does make sense to start at that end, so that you finish at that end as well, making the ride home to Vaughn shorter, but you could do it the other was as well, starting and finishing in Riviere-Beaudette.
You might find it helpful to read the US E2E page also, which gives more info. It states: "you must ride the entirety of the selected Interstate
from and to its opposite endpoint coordinates."
That page is
HERE Scroll to the bottom of the page to read the rules.
I hope that helps.
@Ira can offer official comments if I am off base.