Re: Leaks when it rains.
Glad you found the leak! I was thinking it might be a chainplate when you said it was running down the bulkhead. I would suggest that you sound out that bulkhead and see if you've got any rot. If the previous owner didn't bother to replace zincs in 9 years, it's likely that this leak has been going on for the same period of time, enough to weaken the bulkhead.
You could also take an awl or an ice pick and see if there's any soft wood around where the chainplate attaches.
Another place to look for leaks are the cabin top handrails if you have them. After alot of searching on my boat, they proved to be a source of several leaks, and they will travel between the deck and the liner until they appear somewhere in the cabin.