
Originally Posted by
glc
Okay.......
1. From I-70 to Zion, US-89 to UT-9 is the best way as long as the tunnel in Zion is open. If it's not, then you will pretty much have to take I-15. Note that this route will take you near Bryce.
2. Weather permitting, the BEST option is take UT-24 off of I-70 past Capitol Reef (worth a short visit) to UT-12 to Bryce. UT-12 is one of the most scenic highways anywhere, but I stress - weather permitting. Then you can take US-89 to Zion. However, you would pretty much be committed to the tunnel and there aren't any really good ways to get over to I-15 from there that wouldn't involve mountain highways (UT-14, UT-20 to a lesser extent) or a substantial detour (go all the way back to I-70 or all the way down to AZ and go through the reservation).
If you have plenty of time, you could take the Loneliest Road - US-50. From Bonneville, take Alt-93 and US-93 to Ely to pick it up. If you stay on US-50, that will take you through Carson City and Lake Tahoe. It will rejoin I-80 in Sacramento.