We have done this drive with a grade schooler and a baby. It is doable. It just takes a different plan than a grown-up road trip.
Pace
Shorter days, earlier stops. A playground or a short trail every couple of hours saves the whole day.
Sleep and daylight
In June it barely gets dark up north. Blackout shades or window covers for the RV or hotel are worth their weight.
Portable blackout shades (affiliate link placeholder)Car seats and the border
Kids need their own passport or passport card. If one parent is driving without the other, bring a consent letter. See the border checklist. Car seat laws in BC, Yukon and Alaska each apply in their own area, so check them before you go.
Keeping them busy
Wildlife bingo, audiobooks, and downloaded shows, since cell service drops out for long stretches.