Since I'm from Alberta, any comment I offer will no doubt make trouble. But here goes.

The humidity level will be familiar to you. Only it will turn to ice at certain times of year. Nobody buys a car from Ontario, because the road salt has mostly dissolved the entire undercarriage. (But that's nobody's fault. See, I'm still being nice.)

If the snow gets too deep, the army will be called upon to dig you out. I'm not kidding, this has happened. We in the West are still laughing. (See, I'm getting in trouble already.)

Mostly, as an ex-pat, I think you'll be welcomed. But you'll get what you give. Canadians are more reserved, and just because they don't scream in outrage doesn't mean they aren't deeply offended. Remember that Ontario is very much United Empire Loyalist in heritage. So if you go marching around with fife and drum, well, you'll get some attitude, and blowback. So don't swing at every pitch, let the small things slide, and you'll be accepted.

Leave most of your guns at home. I can understand why that's hard for a Texan to swallow, but mostly you don't need 'em. Take a shotgun into bear country, sure, and a rifle in hunting season. But despite isolated incidents, "Peace, Order, and Good Government" has reasonable traction here. (Two out of three ain't bad, I guess ;-)

If you can get out of the city, north into the lakes and forests of the Canadian Shield, there's some damn fine country up there. Get to know somebody with a camp (not a cottage, ptui!), bring dark ale and good Scotch, and you'll see the best scenery and hospitality ever. Fishin', too.

(Geez, did I just give a plug for something in Ontario? Hells bells, I must be losing it.)

Hope this kinda helps.
Doug