HELP! Burb died and didn't tell me why

[ajgriffin]

So I have a 71 Suburban that I've owned for less than a month. I have plans to swap out the engine eventually, but in the mean time I've been driving with the 350 the PO sold it with. I've driven it on at least 5 occasions without issue starting...needed the occasional jump start, but overall it was ok. Then I go outside to move it into my driveway an initially it clicked/faintly tried to turn over, so I hooked it up for a jump...nothing. No click, no turning over, not even headlights! I checked the battery and its reading close to 13V, the fact that the lights won't even come on has me scratching my head.

Where should I start troubleshooting?