No power, nothing

You gotta have "power" to have a drain on the battery. In spite of a drain, everything else would still work as long as the battery is charged up.

"tried new battery and alternator, nothing. Checked fuses and some wiring, nothing."

What does "nothing" mean? No problem was found? Nothing is wrong? Nothing is working?

The generator won't make the electrical system dead. It just keeps the battery charged after starting the engine. If a lot of dash lights lit up, that suggests a circuit failure, typically due to a blown fuse but it could also be due to a corroded terminal in a connector, a rubbed-through wire that grounded out, or a computer failure.

When the entire electrical system is dead, diagnosis is rather easy when you start at the battery with a test light or voltmeter and work your way down the cables until you find the spot where voltage is lost. That could be a loose wire from the negative battery cable that bolts to the body, or more commonly the smaller positive wire that bolts to the under-hood fuse box.