Met a few people in the past 6 months who've been heading east or west.
Last year was bad because a lot of VIA Rail wasn't running and neither were most of the bus companies. Greyhound used the pandemic as an excuse to pretty much tap out of Canada. The smaller bus companies started ramping back up in August/September and a reduced VIA service from Winnipeg to Vancouver apparently came back in December.
As of right now inter-province flights are still happening without any requirement to quarantine.
Driving/hitching across should still be fine too, but watch out if you have a license plate from another province. There have been a few stories of cars getting vandalized, although to be honest i doubt that's much different from the usual shit out-of-towners cop in rural and holiday destinations.
People are hopping freight no problem, that obviously bypasses any restrictions.
There has been some chatter about shutting down the western provinces, especially since it seems BC and even Alberta are flattening out the second wave, but nothing is confirmed yet.
This site suggests Maritimes and northern provinces are still checking travel documents on the roads: Provincial and territorial restrictions - Travel restrictions in Canada - Travel.gc.ca - https://travel.gc.ca/travel-covid/travel-restrictions/provinces. You can probably get across if you have some work waiting for you.
Apparently a few first nations and other indigenous communities aren't letting folks in at all, which fair enough since they're pretty small and vulnerable.
TLDR: travel between QC and BC should be fine for now, but things might change.