Mid October is also a rather busy time to visit the area because you might hit the tail end of foliage season (the leaves have only barely started to change color here in central Maine where I am right now). Just be prepared for warm days and cool nights.

I'm not hugely familiar with Provincetown, but I have heard it is very eclectic and I bet you would find both good nightlife and very fresh seafood there. I recall that the Provincetown tourism website (I don't recall the exact address at the moment but you should be able to google it) is very thorough.