best routes for Zion and Bryce

US 89 is good on the east side of Zion and west of Bryce. Good road. Most of the rest will depend on which way you're coming from.

Would avoid Hwy 9 with the rig but definitely drive it with the truck - not only the tunnel but it is steep and curvy.

But, like has been said, if we knew a little more of your itinerary we could help better.

Want to go to both parks, camping somewhere in between is our only itinerary

Coming from Vegas, interstate 15. How is rt 14 to 89?

You want to avoid the 14. Coming that way the 9 is fine to Springdale / Zion. If you want to get the the 89 you want the 20.

Do be aware that the eastern entrance to Zion has a tunnel that will not accommodate large rigs. I don't know how big your 5er is, but many of them will not fit through the tunnel.

Here is information on the Hwy 9 east entrance to Zion. It is not only the tunnel but the switch backs dropping down into the canyon. There is height, width and length restrictions.
Zion Hwy 9
You neeed to post your basic plan. You may want to come up or down US 89 and stay in Mt. Carmel and day trip into zion.

Lauren wrote:
Would avoid Hwy 9 with the rig but definitely drive it with the truck - not only the tunnel but it is steep and curvy.

I'm in that area now and considered a drive through Zion with my dually TV. According to the park web page, they regard a dually as a large vehicle and charge $15 to escort you through the switchbacks on route 9.

There is no longer escorts. There is flag personnel at the tunnels. Switch backs are on your own.

To get to the area from Vegas use 15 north to exit 16 to Rt. 59 to 389 to 89 near Fredonia, Az. Take 89 north to the area you want to be in. No tunnels, no switchbacks. There are many campgrounds in the area. We stayed at Bauer's Canyon Ranch in Glendale which served our purposes well. It is between Bryce and Zion.