I am from Barrie. Last time we drove was 2011 and took I-75. If memory serves me correctly, we left Barrie on Thursday around 5 am. Car was fully gassed up an ready to go and snacks and drinks were in the cooler in the back with DD. Took 407/401/402 and crossed at Sarnia Blue Water Bridge around 8:30 or 9 - yes we made FANTASTIC time and beat all rush hour traffic. We had no wait at the border. Stopped 3 or 4 times for gas/pee/snack/stretch breaks. If we had to do one, we tried to do them all. Finally stopped in Clinton, TN for the evening around 5 or 6 pm. Swim, dinner, sleep and back on the road around 4:30 am. We took a slower pace because we were TIRED but were checked into our hotel room and sitting by the pool eating pizza before 6 p.m. When we go this year we are taking an extra day though to do the drive down and to account for traffic and bad weather.
I don't remember spending a lot of money on tolls at all. I think I had $20 worth of American change in my little coin purse I kept in the car for just tolls and we didn't use it all.
On the way home we stopped at the Cumberland Inn in Williamsburg, KY. We loved it and will definitely stop there on our next trip.