Use the southern by-pass around Zion from Hurricane to Fredonia if you are still pulling the 45', and then north to Kanab and up to Panguitch and over to Ruby's. There are some neat arches you drive thru going east from Panguitch, but in Zion, the tunnels are going to be tight for a rig your size, and you'll "love" the switchbacks. The Park charges for your big rig, but let's the cars follow you, so if you get hung up, they are in the way. I would recommend you drive thru in the pickup though, it's worth it. We towed doubles (FW and Boat) thru there in 2002, it freaked the gate dude out!