Time of year?
Spring, summer, fall 2017 will be a poor time to visit Arches due to road work inside the park.
Such a trip can take a few days in the interstates at 6-8 hours driving a day.
Or a month at a better pace of five hours driving per day.
You will see more variety of scenery moving you route north. Though Texas is long and the western half of the state can seem like just miles and miles of miles and miles.
Natchez MS
Nacadoches, LA
Hill Country of central Texas - Fredericksburg, TX
Carlsbad Caverns
White Sands
Grants, NM or Mesa Verde NP
Walnut Canyon near Flagstaff is a half day stop
We loved Zion, Cedar Breaks, Capitol Reef, Arches/ Moab, Valley of the Gods, Monument Valley this past Oct & Nov. Spent five weeks in Utah.
Also loved Valley of Fire State Park a bit north of Las Vegas.
Frankly with the ages of the kids, I'd recommend the Tennessee / NC mountains, maybe as far west as the Mississippi River if making the trip after school is out.
The younger one is going to get tired of moving and sightseeing every day of two. The older one will likely want something like an amusement park or water park a couple times.
The older one will likely go into withdrawal since her phone won't get a signal at many of the national parks and monuments in the west, or for hours of driving off the interstates.
Get the older kid involved in planning the trip, and even daily navigation. Use the excuse that they will need to know how to do this in a couple years when they get a drivers license.
Kids like trips more if they get to pick a stop or three, and do s little research on what there is to do/ see.
Full-Time 2014 - ????
โNot all who wander are lost.โ
"You were supposed to turn back at the last street."
2012 Ram 2500 Mega Cab
2014 Flagstaff 832IKBS TT