Vegas and Salt Lake Airports are about equidistant IF you plan on
visiting all of those. Arches and Canyonlands are a good two hr drive
from Zion, and are easier to get to from SLC, but Zion is about 2 hrs
north of Vegas.I'd just fly to Salt Lake. It's a scenic drive through
Utah, and you'll pass a few state parks along the way...Just watch out
for the drunken indians...(just kidding).