Zion to Bryce

14 is steep up a 4000 foot elevation change. I would take 20.

We just finished our trip out that way. We really enjoyed Hwy 14 if you like scenic drives. You did not say what you would be driving! If RV 14 maybe not so much, its very do able but you would not beable to take in as much of the sights.

Hwy 20 on the other hand is just a great Hwy!

On our way back from Bryce we took Hwy 20, all seemed fine. On the way there from Zion we did backtrack a bit to Hurricane and took Hwy 59/389/89 through Kanab. Very hot, but nice ice cream shop in Kanab.

We recently took I-15 to 20 to get to Bryce -- a very pleasant and easy drive. I think 14 may be more scenic but a little twisty -- I have never driven on it beyond Brian Head.