LifeLabs (
https://www.lifelabs.com/flyclear/predeparture/?myProvince=bc) are offering pre-departure tests for $150 (+tax). Specimens can be collected at Shoppers Drug Marts in Kamloops and Kelowna for the interior, but those are the only interior locations. West Vancouver Shoppers Drug Mart is the closest specimen collection to Whistler.
I also understand that there are self-testing kits that are offered to those arriving in Canada and are required to take post-arrival tests. These are done under medical supervision via videolink. I suppose it is possible that these could also be used as a means to collect specimens for pre-departure tests too.
As
@main street says, it is going to be a wait and see situation - things are certain to change as international travel opens up.