Family National Parks Road Trip

Lwiddis wrote:
If you want your kids to dislike RVing take your outlined trip. It’s too long in time and miles. Regarding Death Valley are you ready for 115F+? Grand Canyon 107F+? If you can get reservations I’d recommend CA1 & US101 north to Olympic NP and home.

The ultimate boring trip for teens. I'd suggest trying to hit as many theme parks as you can get to in three weeks. If they were boys I'd suggest visiting minor league baseball parks. Even campgrounds with outdoor pools.

I disagree, partially. Starting in 2012-2017, from our home base in VA, with 2 boys 12 & 9 yo at the time, we have taken every summer to do a major trip out west such as the OP is suggesting, 4ish weeks in length, once 60 days for Alaska. Many times we were one of the only ones in the southern parks because of the heat. DV was so hot, our AC couldn't keep up. But we still had a blast. Our kids can brag that they have been to over 50 National Parks/Monuments when their classmates haven't even left their state. You really saw a real live bear??

My kids thoroughly enjoyed seeing all the parks, all the critters, exploring, doing hikes, etc. Our BEST memories as a family were made on these summer trips! We raised the kids to enjoy nature and hiking from the beginning. Our thousands of trip photos scroll on our TV background and we still comment on this place, or that animal, or remember when that crazy thing with the moose happened? Haha. How often will you have the chance to do an epic trip with your girls?

Boring? Our boys couldn't care less about baseball, or a ho-hum pool. Theme parks? Spend a long day at your closest one, that is enough of that.

However, for the time the OP has, the mileage and driving is too ambitious. And the twins will undoubtedly make things much more unpredictable and difficult and cranky in the car.
Pick one general area of the country and hit all the parks there in a more reasonable driving loop. Two days in any one of the big parks is really not enough to see and do it all, but better than nothing. We were able to get only 2 nights at Zion, not nearly enough, but better than nothing. We will have to go back. Yellowstone, for ex. has huge driving distances just between the several different areas to see. You'd be limited to seeing just the Old Faithful area.

We had to make campground reservations many months in advance in the past and plan the trip down to a gnat's butt to make the scheduling work, now who knows with the virus? Several parks will have Nat Forest land or BLM nearby for possible camping options, but adds to headaches of driving into park for the day, wastes precious time.

We hauled 4 kayaks, and 4 bicycles on our first cross-country trip, and while we kayaked in Yellowstone and Teton and later in Everglades, the bikes never got used. It is better to bring a minimal amount of baggage/toys along for such a trip. The time and logistics required to maneuver all that on a daily basis...when you are already on a rushed timeline and have 6 people to deal with...

Just my 2 cents.