We had a similar time frame and distance when we went in '14. We had a flat in Duluth, thankfully fixed same day! Cracked oil pan on the toad in White River, fixed with JB Weld in Whitehorse. Other little problems and we still limped home on time.
Our plan was always to take what happened and adjust from there. If we were going to be delayed we just wouldn't see something farther down the road, all part of the grand adventure!
Enjoy the time with your family no matter what happens! Time gets away from you quickly!