A few thoughts...

Vancouver is a very nice city but I felt like I had seen it in about a day and a half. Toronto is similar - but even less interesting to my tastes.

Montreal is a great town that I would love to visit again. You could combine that with a trip to Quebec City which is beautiful. It will very much feel like a European vacation - particularly in Quebec City. Stay at the Chateau Frontenac.

Alternatively, Calgary is a serviceable city and would be fine for a nice dinner and concert. Calgary's main advantage is that it is only a few hours from Banff. It might be chilly that time of year but Banff and the surrounding national parks are spectacularly beautiful with lots to do if you are outdoorsy.