Another good ride for training is the Boundary Bay Park shore-side trail between Centennial Beach in Tsawwassen and Mud Bay in South Surrey. It's about 40 km return and has a head-wind in both directions.
During busier times the Tsawwassen side has amenities, but once you hit the trail there is nothing. Be sure to have water, snacks, and repair stuff with you. I have gotten a few thorn flats over the years.
The surface is mostly light gravel and pretty much flat, but it's a really nice ride.
