Coming for NAB by any chance?
To answer your questions:
So, can I just OC around town or what?
--yes, OC is legal in all of Nevada. Obviously federal laws take precedence for federal buildings, and private property is up to the discretion of the property owner, casinos included.
How about in the car?
--Yup. Rifles must not have a round in the chamber, but pistols can be loaded and chambered and placed anywhere in the vehicle, including on you. Being obscured by the vehicle or parts of it while on you is ok, but being obscured to the point it becomes unrecognizable as a gun by you or something on you is concealment.
Do the LEO give you much trouble?
--LEO hasn't given much trouble in months, and members of the site have done OC meetups in areas all around Vegas in direct view of LEO without problems. The only outstanding issue is local parks. There is a "law" on the books that should no longer be enforcible, but LEO has vowed to enforce it anyway, so stay away from parks unless you want to test it.
Can LEO stop me and run my numbers?
--Legally, no. However, it's been determined that the LEO will do whatever they see fit at the time. You can then file complaints if you wish, which to date have been useless as they seem to choose not to investigate the items that are obviously in violation of law or protocol.
Do I have to talk to them or (as long as I'm not being "detained") can I just walk away?
--If you are driving, you must identify your self, provide a valid drivers license, and proof of insurance. If you are not driving, you need only provide your name. Any other questions need not be answered, you can invoke your rights at any time, and should. Best practice is usually to not walk away however, consensus is generally to frequently ask "am I being detained or am I free to go?". You may choose to walk away if they are not detaining you and won't answer. Ultimately up to you, YMMV, but your rights are yours to enforce, and your freedom is yours to risk.
The FAQ is a great idea. Searching is good too.