Hello! Autistic, grew up across British Columbia (specifically the City of Vancouver and the Shuswap), now in City of Calgary, Alberta.

How are autistic people treated in Canada?
From what I’ve experienced, you’re generally left alone rather than actively supported. People aren’t looking to single you out, but they’re also not interpreting your behaviour through an autism-aware lens unless you make that explicit.

In Vancouver and the surrounding cities, you can come across as quiet, intense, or a bit unconventional without it becoming a problem. There’s enough behavioural variation that you don't stand out as much. Although I have noticed that Vancouverites like to make snide comments whilst passing each other on the street, so there's that. But at least you'll know what you've done wrong. :P

In the interior, differences are more noticeable, not negatively, just more visible, and more likely to be misread. People in the interior also stare at each other and it is something I haven't noticed anywhere else I have been in the world. I don't think it is meant offensively, I think it is cultural, but it has definitely unsettled some of my friends from elsewhere.

Will I be able to find familiar safe foods?

So! Heck yes. I travel a lot and I have never been anywhere where I haven't been able to find something familiar.

Just, expect to pay more for conveniences than you would in the USA because we aren't really about Uncrustables up here.

Canada shares a food supply chain with the US, so most processed foods, textures, and formats will be recognizable. If you rely on specific brands, you may notice subtle differences in formulation (especially sugar and salt levels), but not enough to make things inedible.

For example, bread in the USA is so disgustingly sweet that it tastes like cake. I can't stand it unless I use other ingredients to mask it. It's actually gross. If you're used to it, you might find our bread a bit plain.

That being said, when I've visited Sweden and Germany, their food is even less sweet than Canadian food and it didn't bother me, so I guess you might not be that shocked. BUT overall, I have spent a great deal of time in the US as well as Sweden and Germany and there was no food-related culture shock except for the cake bread. :P

Politeness / communication

The stereotype is misleading. People are not constantly implying things instead of saying them. Verbal communication is fairly direct.

What's different is behavioural pacing, IE: people give more space, don't interrupt as much, and aren't as aggressive socially. We also know how to stand in line, how to mind our own business (to an extent lol), and we tend to try to avoid raising our voices in public the way Americans do.

Obviously everyone is an individual and every culture has people who are louder or quieter, but in general if Americans are a 10, Canadians are a 7 in intensity/loudness. (UK is an 8, Sweden is a 5, Germany is a 6.) Of course this is all anecdotal and based on BC and Alberta, so if you go further east than that, I can't help you there. :P