Electrical issue-dead battery

My 2001 Windstar has been moved to "backup" status, partly because it would randomly kill the battery. I've had both the battery and the charging system and they check out OK(per AutoZone testers).

But now that it sits, it dies fairly frequently. I put in a freshly charged battery yesterday and it starts right up. I let it idle for a while I cleaned it out a bit and I noticed the brake lights were on. I pulled the pedal up by hand and the lights went out.

I don't see a way to adjust the switch but I figured if they were out, everything was fine.

Tried to start it this morning and it's stone dead. One weird thing I noticed was that when I rolled the key back to the "Off" positions, all the gauges sweep up to their full limit, then go back down. I don't recall them doing that when everything was working normally.

Is that a clue for anyone or am I getting ready to call "cash for junk cars"?

At 233k miles, I don't want to put a bushel of money in this thing. I can fix anything that's wrong, but I honestly don't know where to start looking for this problem.

Thanks in advance for any help!