Do forgive me if this is a stupid and/or obvious question, but what's the rule on acronyms like NPR and school names? Must I spell out everything the first time, or can I assume that it is acceptable to label major entities like NPR and the LA Times as such?

Spell out. However, if you are going to refer to it multiple times, you may write something like: National Public Radio (NPR). Then, you can refer to it by the acronym from that point on.

Excellent, thank you.

Love your SN, by the way. I think I'm more fond of Stupendous Man, though.

Me, too, but for those uninitiated, it just comes off as horribly narcissistic.