1. No law really governs OC in Nevada, so let's put it this way: there's no law prohibiting a non-resident from open carrying in the state. There's also no law prohibiting a resident from open carrying, so both the resident and non-resident are in the same category.
2. From stories I've read back and forth various forums, I think it'd be easier to get your non-res permit in Reno. Or maybe to be fair I should say anywhere that isn't Klark Kounty. I'm sure you'd be fine dealing with the Metro PD down there if you chose to do so, but it might go a little faster and easier if you do it in any of the smaller counties.
One example I hear a lot: guys in Clark County have to wait for Metro to send them a permit with updated address in the mail most of the time, whereas in Washoe County up here you can stand in line at the CCW desk and have a new card in about 15 minutes.