reservations around Penticton, BC

Planning a road trip that will go to the rodeo in Calgary in July, onto Banff for a few days, and then swing back thru Kelowna, Penticton, Okanagan Falls area on our way back to the Seattle region. Do/should I make hotel reservations for the Penticton/Okanagan Falls area (would be on a Sunday night) ahead of time, or can I just "wing it"...i.e., will there be lots of choices (even though it's mid-summer) or is that too risky? (I don't really want to be 'locked into' a specific town, but neither do i want to not have any place to sleep that night). thanks.