Leaving out of Gold Canyon, Which way to Flagstaff?

The Payson route is very scenic, especially HWY 3 (Lake Mary Road) from Clint's Well to Flag. (Watch for elk in the late afternoon / early evening!)

Most of the grade on 87 is four-lane and not much different than the grades on I-17, HOWEVER there is a short stretch of two-lane climbing out of Payson to the top of the Mogollon Rim that is two-lane and a bit twisty-turny. Not sure what that would be like with 70' of rig. Check google maps for a visual.

From the top of the Rim on to Flag is two-lane but smooth sailing.

Ellsworth to Bush Highway to 87. Turn at Clints well onto state route 3 (Lake Mary Rd) to Flagstaff.

There is an 11 mile grade heading into Payson. It is 4 lane, divided. From Payson to Pine/Strawberry there are a few shorter grades but aren't bad. After that it's fairly flat to Flagstaff. Very scenic drive.

Check weather. Snow is forecast today and later in the week. During day time hours it probably will be to warm to stick on the roads.

In a car or standard RV we usually go Payson, Happy Jack, and Flag.
I had no problem with my 38 foot DP towing a CRV.
At your length, I might revert to I-17.

Use Google Maps to route the trip. Then change to Bicycle mode (icons across the top). Scroll to bottom of text directions and you'll see an elevation graph. Look at both routes. (Note...this is on computer, not phone app which I don't know if the same display.)

I often try to take different sections of route on our trips around the U.S. where we've been before.

As others note, just be sure to check the weather and road conditions before you go......AZ511.com or call 511 for road conditions/closures.

Roughly 182-185 miles either way
Roughly 40 minutes longer via 87

Recent storms have dropped snow (Payson---north to Flagstaff)

87 is more scenic

Been a number of years since I been there, and not in the RV, but 87 is about the same distance and certainly more scenic. But as I remember lots of winding curves and ups and downs and narrow two lane with little if any shoulders. Ultimately you still have to climb the same total in elevation. But I think due to ups and downs there will be more total up hill towing and more fuel usage.

Take a look at google maps street view to get an idea of the highway.

If your going to go to Flagstaff, your going to go thru the mountains.