It would be a church. Yes, there is an enormous difference between a church and a temple. Churches are where we hold our regular Sunday worship services, and they are open to anyone, LDS or otherwise. There are thousands of LDS churches throughout the world, but over about 120 or so temples. Temples are where we perform sacred ordinances that have eternal significance. Only members of the Church who are living up to a specific standard are given the opportunity to participate in temple worship. (Prior to when a new temple is dedicated, though, it is always open to the public for a few weeks.) I'd guess the closest LDS temple to you would be the one in Montreal:
If Jordan St. Francis is in St. Catharines, the temple in Brampton would be quite a bit closer than Montreal:
Toronto Ontario Temple Main
(they call it the "Toronto" temple on the web site, but it's really west of Toronto in a suburb)
But from where he is, it'd be a toss-up whether Palmyra, NY would be even closer than Brampton.
My impression is that there would be more for a non-Mormon to do and learn in around Palmyra than at most temples. At a temple, all a non-Mormon would be able to do is stand around outside and take pictures; near Palmyra, there's the Hill Cumorah information centre, which AFAIK is all open to non-Mormons.
BTW - Jordan or others: if you get out to Vancover at all, keep an ear to the ground for when the open house for the
Vancover Temple is. It's under construction right now; the date for the open house is currently TBA.
Also, for Jordan: since you said you like photos of cathedrals, have a look at my RF gallery for the few I took of Basilica Notre-Dame in Quebec City:
My Photo Gallery - 9-10ths_Penguin Gallery - Powered by PhotoPost
For "the seat of the primate of Canada", it was strangely monkey-free. I was disappointed in that regard, but the church itself looked nice.