Thank you for the follow ups. Yes, long term storage is quite important to me. Last year a great many of my squash were not ideal even when not stored long (as stated in the OP, I picked the bulk of the crop on August 15). I resolved to leave 2013 squash on the vine until well into October come hell, high water or an army of critters (in my yard that means squirrels). Some years ago, IIRC, squirrels weren't a problem, but for around 4 years running now, they are a huge problem every year, that in spite of my having deposited two of them in the park ~6 miles away and killing one with a rat trap. I stopped setting rat traps, I've found the squirrels trip them and generally seem unfazed. One time, however, one did die. This year a squirrel (I assume it's only one, but who knows?), has tripped my trap but somehow not been caged. I figure sooner or later I will get him/her, or else the beast will wise up and stop hitting the trap. They do seem clever at times. I'm seriously contemplating buying a pellet gun. I'm curious, is there a way I can configure things so I get emails when someone responds in this thread? I have not seen that in these forums yet, and I did look today when I registered and posted this. I only see something about allowing people to post me directly through email, which I'm not sure about.

In my zone I'd probably give them a few days longer. When the rind is so hard that you can't dent it with your finger nail and stem is fully dried is pretty much standard and you aren't to that point yet, right? But in your zone IF the rind is fully hardened I'd probably pick them now rather than risk them to the weather. They will finish ripening indoors in storage. Dave

The link below is to a lengthy post about butternuts in particular, but it applies to all winter squashes. Scroll down and you'll see the recommendation to give them a mild bleach rinse, about 1 part bleach to 10 parts water. There's curing info in there, too, if I remember correctly. I leave mine in the garden until the stems are totally dry (here that will probably be another 2 to 3 weeks, but definitely before the first frost). By that time, the vines are usually totally dead. I do put some straw underneath to keep them off the dirt and let some air circulate. Here is a link that might be useful: Butternut Squash Post

I can't say what's absolutely the best. But what I do is leave them all on the vine until harvest time. For me harvest time is when all leaves are dead, even the newest leaves on the outlying lengths of vines. And the stems are dead. If I notice any that are too immature to ripen on time I cut those off and compost them. I'm always looking for those a month or two before anticipated harvest time. I also don't cut the stem, but rather the vine on each side of the stem. So if I was harvesting some now and some later I might be cutting some critical vines. I have no idea if there is any benefit to this but it was recommended by Amy Goldman in her book "The Compleat Squash". In my garden I'v stopped watering as there are so many fewer leaves and the days are shorter and cooler and vine growth has stopped. The remaining leaves do not wilt so I'm guessing water isn't an issue and I am more concerned with excess moisture in my winter squashes than not enough. And there is certainly some water down in the soil to draw upon.