We made a trip in June 2015 to destinations including the Grand Canyon on the way to Yellowstone NP. Towed a 30ft TT with a 2007 Chev 2500HD. Departed Lawrenceville, GA with the following stops on the way to Grand Canyon.
I20 from Atlanta to Vicksburg, MS.
Ameristar RV Park, Vicksburg, MS
https://vicksburg.ameristar.com/hotel/rv-park/
Visited Vicksburg National Military Park - Definitely worth the time.
I20 thru Dallas and Ft. Worth, Camped in Walmart parking lot, Hudson Oaks, TX. Several RVs parked there, no restrictions. Nearby campgrounds all booked.
I20 thru Dallas and Ft. Worth was in terrible condition, maybe better now but I doubt it.
Route to Amarillo: Texas Hwy 180 to Hwy 51 north to Hwy 920 to Hwy 199.
Hwy 199 towards Joplin, Hwy 114 towards Jacksboro, Hwy 114 to Hwy 281 towards Wichita Falls, Hwy 287 towards Chillicothe, TX and into Amarillo, TX. Roads were in great condition, better than Interstate. Great Texas scenery.
Camped at Amarillo RV Ranch RV Park (Owned by Big Texan restaurant). https://amarilloranch.com/. Big Texan restaurant is home of the 72oz Steak dinner. If you can eat it in the time allotted, it's free. We didn't try but watched several try. Very large restaurant, great service. Free shuttle from RV part to restaurant.
Route Amarillo to Albuquerque: Hwy 87 south to Canyon, Hwy 60 west towards Dawn and Hereford and thru Friona and Bovina. Hwy 60/84 to Fort Sumner, Hwy 60 towards Encino. Hwy 285 north to I-40 and I-40 west to Albuquerque, NM. Camped at American RV Park, Albuquerque (http://www.americanrvpark.com/ ). Visited old town but not much else.
Route: Albuquerque, NM to Winslow, AZ. Stopped and visited Petrified National Forest along the way. The park is definitely worth the time. What I found amazing was there were MANY signs in the park warning you not to disturb the petrified rocks, etc. However, once you exit the park there are thousands of specimens along the roads and many shops selling petrified artifacts.
Camped in Denny's parking lot adjacent to Flying J Truck Stop, Winslow, AZ. Several RVs parked there. No issues.
Route: I-40 West from Albuquerque to Petrified National Forest. We Drove thru park and exited on Hwy 191 to St. Johns, then Hwy 1-80 to Holbrook and I-40 west to Winslow, AZ.
Route: Winslow, AZ to Williams, AZ. Route: I-40 west to Williams, AZ then onto Hwy 64 to campground. Camped at Grand Canyon/Williams KOA campground and used it as a base to visit south rim of Grand Canyon. Drive from campground to park entrance was about 30-40 minutes each day. Stayed 2 days. http://koa.com/campgrounds/grand-canyon/
Traveled Hwy 64 north from campground to Grand Canyon National Park and back to campground. We stayed 2 days then departed north to Bryce Canyon NP and then on to Yellowstone NP via Salt Lake.
Good luck on your trip.
Reggie