By 'layer" do you mean 'tip layer' or 'propagate' the plants? You need at least a few weeks at temperatures that will support plant growth and damp soil helps. What variety are you tip layering? I have both Royalty and Glencoe but Royalty is too erect to tip layer.

I don't know what the difference is between the two methods. And I don't know the type; they are summer-bearing purple ones that my father planted 40 or so years ago. They were down to one plant when I bought the family home four years ago, but I've propagated into about 15. I can't remember whether I buried just the tip or whether I buried part of the vine. Both seem to work for raspberries.

We have a 50% chance of a 32-degree night by October 11th.

Well it can't hurt to try. I'll take some! You should spread them around, keep the line going. I see more extinct lines than ones that exist.

Good idea. I have probably 20 vines just laying on the ground waiting to be used. I made a note to look you up in April and send something you way.

Hopefully I can find some time this weekend to work on them.

Even if they don't root this fall they will root next spring using simple layering. I use layering when the sun is not to hot and the ground is moist enough. Fall and spring are the suitable times of the year here.

Here is a link that might be useful: layering

Thanks! Sadly it's up to us gardeners at times to keep these lines going. I'm trying to pass around Anastasia wyeberry, and I also have Burbank's white blackberry.
Nettleton's creamy white blackberry too. Hopefully I can keep them going all young right now. Passing on wyeberry to two people or trying to. I planted a cutting that took well, and tip layered another that recently just died, bummer. The person may have to wait another year.
I'm new to this, and not equipped to propagate, doing the best I can. Try finding any of these for sale. Burbank was such an important figure, that plant needs to survive!
In the future I will offer these up to whomever wants them.