Go For It
Used Harv's Air for a number of my ratings. Good organization especially for helping out non-Canadian pilots. Lots of experience in that department.
If all you're going to do is eat, sleep and fly. Then Steinbach is fine. If you're going to occasionally make use of a real city, then it would be better to do it at their St Andrews location.
As for the Winnipeg Flying club... It went under. I understand its re-constituting itself, but not a real option in my opinion. In fact Harv Air's facilities are the old WFC ones' They purchased them when they went under.
Check out their site, and give them an email/call to discuss getting a PPL in 4 weeks. I think if you have the ground school done when you show up, you can do it D/L, then the flying should be straight forward. Flying weather is usually always good, albeit cold in winter. But with the long summer days, any thunderstorms should only cause minor delays.
I would say go for it. They are a trustworthy school. Its a family school that was started by their father (Harv) who has more or less withdrawn from the running of it. Their expansion over the last couple of decades has been very measured, so I would say their stabiblity is good. So do not worry.
Hope this helps,
Dan Zegarac.