Spark plug thread excepted I hope all is well with Pat and yourself and that your trip is going well.
Your problem may have been caused by not copper based greasing the thread before screwing the plug in, use a small amount each time it goes in to avoid this. Depending on how much metal came out with the plug it might be alright until the next time it comes out but it would be wise to get it helicoiled at a convenient point along with the rocker cover threads, it should be no problem for a competant mechanic or engineer to do this.
With the regular mentainance and use it is getting I would have thought your engine should go on for 80-100,000 miles so plenty of life left yet.
If gaffer tape doesn't fix it then you haven't used enough tape