2003 Taco-- 62,000 miles

I was 40 miles outside of Raleigh, NC. Had been driving 11 hours from NY. All I could think about was my bed. Suddenly there was a loud chirping from the engine. It lasted about 20 seconds then stopped. Then it started again, followed by a bang, and then the engine shuddered. I pulled over.

Looking under the hood, the center spark plug on the passenger side had basically blown out. All that was left was the coil pack, with nothing below it. (Not even the rubber.) Because it seemed the cheapest option at the time I had it towed to the dealer in the town I was in.

Their explanation was that the plug was too loose. (Was this the clicking I had been hearing the past month or so?) The loose plug finally blew out, taking all the threads with it. If you tried to put a new plug in it the way it is, it would drop down into the combustion chamber. (Or whatever it is that's below the plugs.)

Does a loose plug seem the likely cause? What was that chirp right before the bang? (The bang being the plug hitting the underside of the hood.)

I haven't done anything yet. I've been making calls and such all weekend. Basically I've been given these options:

1. Replace the whole head with a new one. Obviously the most expensive.
2. Fit the head with a helacoil. Slap in a plug and a coil pack.
3. Put in a used head.

All of these would be done by the dealer where it is.

I have a fourth option, but this involves towing the car about 100 miles to a friend's shop. He's been a mechanic for 30 years. I trust him. (sort of...ha!)

He's willing to do it for next to nothing. I'd help him, which would be a good learning experience and all, but I'm not sure the tow would be worth it. We'd explore all options above.

Any thoughts?

(Sorry for the long post.)