When, where, and why?

Any answer will consist largely of speculation anyway, but unless you can provide the above it's unlikely it'll be of much use. For example, I can cross the border right now if I can give (and substantiate) a valid reason, e.g., an essential occupation. Earlier in the course of events I could have crossed to visit with immediate family, which I've got, but I understand that's no longer true. Transport of commercial goods is supposed to continue unimpeded, but entering Canada for purposes of recreation and tourism is totally forbidden (not that much is available these days--in BC, everything's shut down cold).

I'm guessing (<-deliberate choice of terms) I could still enter Canada if, say, my sister were sick. In practical terms, the border is a 25 minute drive from my house, so I wouldn't be risking much if I tried. That's not so much the case in Springfield MS. Crossings in my neighborhood have fallen by ~98%.

If flying, just ask your airline (if you can get through over the phone); they'll have up to date information, mostly, because they don't want to have to ship you back home if you're refused entry. Do bear in mind that AFAIK there is currently a mandatory 14 day quarantine upon entry at your own expense--if you don't have this set up in advance, the Canadian government says it'll assign one, charging appropriately for the service.

If you're wondering about a summer vacation, there will surely be major differences between May 15th and the end of August. If I wanted to inform myself of future possibilities, I'd be reading the major Canadian newspapers for clues about what the summer might hold. Of course, they're guessing too...

Don't know if that's helpful, but I hope so.

Mark