Here is the link to the old BC Rail timetable. I don't think we should expect dramatically different times.
https://wx4.org/to/foam/maps/2-Perry/014/014b/1987-05-10BC_Rail_PTS12-Perry.pdf
It is about one hour between North Vancouver to Squamish Station. That includes a scheduled stop at Horsehoe Bay and five flag stops. Whistler is another hour north.
We know its going to be hard to justify this financially. Lets assume we can. What probably makes sense is to base a train out of Pemberton.
Pemberton - Squamish - North Vancouver - Squamish - Pemberton
7:30 AM - 9:20 AM - 10:30/10:45 AM - 12:00 PM - 1:50 PM
2:00 PM - 3:50 PM - 5:00/ 5:00 PM - 6:15 PM - 8:00 PM
If money was no object you would add a second train set
Pemberton - Squamish - North Vancouver - Squamish - Pemberton
5:30 AM - 7:20 AM - 8:30/8:45 AM - 9:00 AM - 11:50 AM
12:00 PM - 1:50 PM - 2:00/ 2:00 PM - 3:10 PM - 6:00 PM
Play with the schedule a bit but you likely have the two trains pass each other in Squamish station maybe at one of the old flag stops.
If money grew on trees, then add a daily all the way to Lillooet or even up Prince George. That would be extremely unlikely run to justify.