I want to take Route 90 from Clarkson GO in Mississauga to Main and Longwood which is a train-bus route.
It's been several years since I did that and I was wondering how you transferred from one to the other.
I.e. Where are you waiting/going after getting off the train?

I don't know what route 90 is, but if you are going from Clarkson to Main/Longwood:

1. Train from Clarkson --> Burlington or Aldershot (depending on what time of day it is; just wait till the last stop).

2. Bus from Burlington or Aldershot to Hamilton GO Centre (follow people to the way out i.e. where the parking lot/buses are). This one will stop by Main/Longwood. Don't take the McMaster one; that's an express and does not have any stops in between Burlington/Aldershot.

Hope that helps a little...

hope it all works out for ya!