Depends. I'm from NE too. If your cruise is primarily Canada and Northern NE, then early September for the foliage. By October, it's all gone there. If your going to Southern NE, seeing Martha's Vinyard, etc. then around October 8 or so is peek foliage. The cost of your cruise is reflective of the peek foliage season and cruises during those times sell out quickly. Recently I inquired about a September 2005 sail from Boston to Montreal on HAL. It's completely sold out!