If you're flexible in needing full service site or basic as well as time, you should have a decent chance of getting a site at RMNP, check the links mudchucker posted. A couple of provincial campgrounds we like is St. Malo which is about 45 miles south of Winnipeg or Bird's Hill which is about 10 miles north. If you want to spend a day or two in Winnipeg, then Bird's Hill is a good place. There is a Folk Festival at Bird's Hill from July 6-9 and Folklorama runs in Wpg for two weeks from August 6-19. Have fun in our provinces!