What Time is It?

On Thursday we left the Mesa Verde and 4 corners area headed for the Grand Canyon. Thursday's drive was about 480 miles and a 4.5 hour trip.
We were talking about what time we would arrive. We were using the GPS with the address of the hotel that we were headed to right outside of the Grand Canyon. Jeff said, "Wait a minute, there's no way we will get there in 15 minutes. We're still in the middle of nowhere and according to that sign over there, we still have about 1 hr. and 15 min. to go." He was thinking we would be arriving around 8 pm. Now we had stopped to pick up some pizzas that night for supper and I remembered seeing the clock in the place say 8:30. We were thinking it was 7:30. Jeff's phone was saying 7:30 my phone was not charged, and the GPS was estimating our arrival at 9:10. Then I remembered Arizona does not participate in Daylight Savings Time. Thus ensued a discussion of just exactly what time it really was. Cell phones pick up whatever time zone you'r'e in so Jeff just insisted it was about 7:30. GPS is supposed to as well and it was saying arrival 9;10 which would make sense. But the restaurant in Arizona had said 8:30. All of the sudden the GPS "clock box" goes blank. No time estimated for arrival. The car clock is set on Mountain Time which was 7:30. We checked the map, Arizona is in the Mountain Time Zone but if they don't participate in DST it is 8:30 which is the same as Pacific Time. The GPS clock comes back to life and proudly displays arrival time of 9:10. 8:00 pm (wherever it is 8 pm at in this country) comes and goes and we are not there. The GPS hour later. We just went to bed. We're still not sure what time it really was! And I was just trying to remember just when had I fed the baby? All I need to know is when 3 hours has passed.