I've had to run from 69 to 88 due to ground traffic blocking the arrival gate... its a LONG way, especially if you have carry-on bags; took me almost 10 minutes. Your connection is probably safe if you arrive right on time but if you have to wait for the gate or to disembark you're going to have to run or catch a golf cart. Having said that, if I was in your position, I wouldn't change my itinerary, LAS to LAX often arrive early.