Well all went well installing my subs and cd player (will post pics tomorrow), butttt one thing. The passenger side carpet is pretty wet all under the front floorboard. I pulled up as much as I could without taking the seats out and pressed it with a whole roll of paper towels but its still pretty soggy under there. There was so much in the door sill that I drilled a drain hole.
Now, it appears that the heater core was replaced pretty recently, and the carpet did slightly smell of weak antifreeze. The cover on the heater box was hanging down a bit (someone didn't put the back screws back in) and I pulled a couple more screws and the heater core looks brand new. I pulled the carpet way back and ran the truck and no leaks were apparent. The bottom tray of the heater box was dry also. I then poured a lot of water all over the door and windshield on that side and none if it came down the firewall or ended up in the floor.
So, I'm thinking it busted not long ago and it just wasn't cleaned up, but does that sound plausible?