https://www.expedia.ca/Flights-Searc...trip=roundtrip
I would look at these direct flights, you'd be $3412 plus bags, contrary to the other advice I would book this now as this flight will not drop much if any, certain flights only get so cheap and these direct flights are great value. FWIW this is about what we paid in 2018.
You can also look at Turo for rental cars much less expensive and better variety then standard companies, rental prices are insane right now.
https://turo.com/ca/en/search?countr...mDistance=true
Not sure what you have for air miles but I like to use air miles for rental cars when I can. I would not want to do this drive and I like driving. Just so much could go sideways with an accident or vehicle issues being my biggest concern. Never mind 8x 10 hour days in the car with the wife and kids...
You could also drag your feet about going do to the overall cost and see if the parents will cover some of the expenses to spend a few weeks with the grand kids in sunny FLA.