Op you have not said what is the longest trip your family has taken an a vehicle or what the longest one day drive you have taken in your RV is.
We individually, only know how much to too much in our own situations.
Driving in a car without the kids we can do 16-18 hours, stopping at least every 3 hours. But not more than one day in a row. We have done a long day, then a shorter day driving to San Francisco.
With the kids Victoria to Banff (700 miles), is 12 hours plus ferry in a car. Not so much fun, even with toys to keep the kids occupied. We stop every 2 hours give or take and stretch our legs.
Victoria to Banff in Mobi (27 foot C), with kids (plus dog) we do in two days. Once again usually one longer day, then a short one.
From home to Banff is almost entirely mountain driving. We have not driven any great distance on the Prairies, I have no idea how that may change things.
We both drive about equally.
You asked how long it takes to set up and break camp in the morning. That will vary quite a bit. We do not have slides, travel with a full fresh water tank and for a quick overnight, we do not need to hook up.
All we need is to level, stretch our legs then head to bed. In the morning we can just drive away after the dog has been walked.
If you prepare lunch in the morning you will save a bit of time. Usually one of the kids walks the dog, while lunch and breakfast are made, then we hit the road again. Or you can prep breakfast and lunch the night before.
Having lots of healthy snacks seems to help too. We prep fruit and vegies, or buy ready made trays. The kids love to freeze the individual yogourt containers for frozen yogourt etc. Lots of good tasting water as well.
One trip we have junk food snacks and the mood in the RV was not pleasant. Now we keep the junk food for once we arrive. But always stop for ice cream at some point along the way.
We can easily go 3 days without dumping the tanks or refilling the fresh water.
If you plan on getting a campsite (remember it is just about the busiest time of year for RVing), if you have one with a sewer hook-up you will not have to wait to use the sani station. There can be long waits at sani stations, especially on the last day of a long weekend.
If you want a campsite, you will likely have to reserve that close to July 4, you may be required to reserve more than one day. Often campgrounds have a 2 night minimum on long weekends.
You have 6 months before your trip, take a couple weekend trips, see how long and far you feel comfortable driving your RV in a day. See how you are feeling when you get back home the next day. Then try it fully loaded with the kids, is everyone still happy?
My kids are the same age as yours, they have been rving for 7 years, tenting all their lives. We feel lucky that they still like to travel with us.
You are asking the right questions and have lots of time to plan.