My experience with the Bontrager Hardcases was not positive, but San Diego to Phoenix is a short trip.
I found the Hardcases barely OK. They seemed to get kind of soft and sticky after riding in 100+ heat for a week or so and once that happened they seemed to flat more often.
That said I don't get too excited about flat prevention other than watching where I pull off the pavement in goat head thorn country and watching what I run over elsewhere. When it comes to slime tubes, thorn proof tubes, and mr tuffy strips I don't use any of them. I prefer light weight tubes.
I just use a tire that is reasonably flat resistant (Ultra Gatorskins) and don't mind fixing a flat once in a while. It beats having a couple extra pounds of rotating mass and a dead feeling ride in my opinion.