The cab drivers will have no issue whatsoever with this journey. They are very used to short trips around the downtown core.

If you want to walk, enter Waterfront Station, follow the enclosed footbridge over the rail yards, go down the escalator, and follow the "helicopter" signs outside to east parking lot and the heliport. Once outside, it's about a five-minute walk, give or take.

https://www.google.ca/maps/@49.28642...!3m1!1e3?hl=en

Here is a Google Street View picture of the door you will exit from waterfront station. Twirl around and double click your way through the parking lot and you'll see the path to the heliport

https://www.google.ca/maps/@49.28649...2!8i6656?hl=en

I have seen the Helijet shuttle vans around town, although I've never taken one as getting to the terminal is very easy.