Charging to 100% is only considered harmful if not consumed reasonably rapidly. It's only about long-term health as well -- there's no harm in and of itself charging to 100%. For road trips, that's precisely when you want to - time permitting - do this. I would always aim to charge to 80% on road trips but then take that as an alert that I needed to wander back to the car. Usually I was eating, or strolling, or something for fun.
It is also an urban myth that supercharging is harmful to the battery in and of itself. The battery will slurp as much charge as it reasonably can. It will slow or speed up based upon conditions - weather and temperature, battery capacity, etc. When you think about this from a "pull" perspective, it is less concerning than thinking the charger "pushes" and has the potential to damage. Not so.
There is a correlation / causation problem that usually exists with normal battery degradation and supercharging but I've seen no real science to back that up. The only real factor is don't let your battery rest at 90%+ for long term health. The rest is very subjective.
EDIT: I did some research. Heat is a battery killer in general, which is why there is a lot of fan activity when supercharging. I stand behind the general statement that it probably isn't supercharging in general that causes problems (for example, supercharging in colder climates probably won't get you 250kw pull but it probably also won't generate a lot of heat) - but also there may have been improvements in fans and batteries from the X and S.
It's hard in general to say that the supercharging caused a problem in Arizona vs the general hot climate, if you follow my logic. There's not a direct link or a lot of science, and I tend to believe - granted, on faith - that Tesla would allow your battery harm by simply using the tools it has to charge it. The manual directly states an optimal charge % but says nothing about the style of charge. Superchargers are perfectly fine.