This is sort of a trip report, but I thought it would be more useful in the Packing group.
For this trip I sized down to a 20x14x8 Eagle Creek 2-wheel roller bag. The total packed weight was the same as my 22" Lipault spinner, but the smaller size was much more manageable.
As much as I hate layering, I've been a strong advocate for it and done it on trips for years. I thought I planned well for my recent (1 May to 12 June) trip to England and Scotland by coordinating everything so that I could layer anything together for those cold, windy, rainy days. I'm here to tell you that even 4-5 layers (shapewear tank, base layer, long-sleeve tee, button up shirt and wrap) under my rain jacket was sometimes not enough.
And the layers were an enormous pain to put on over each other. That's my major complaint about layering. A shapewear tank, 1 or 2 layers and a jacket are fine. More and I'm whining and cussing. Before anyone suggests cashmere, or merino or anything similar, I have never been able to tolerate any kind of animal hair fabrics in my life, so those are not options.
I could have taken my great Patagonia polyester quilted "sweater" with a hood that I can put into a bag about the size of my fist, but the zipper broke at the last minute and I didn't have time to replace it or get a new similar one or a fleece. So I decided to wing it with what I had, including a couple of base layer tops. Those base layers definitely worked to keep me warm with minimal weight and volume. I wish I would have taken one more of those and left some of the other layering pieces in Tucson. As it was, I gave 2 button up tops to charity shops in England.
I had window shopped warm-looking tops in other places, but while in Kirkwall on Orkney, I actually went into an outdoors store for fleece options, but there was nothing that was big enough for my body and small enough to pack in my tiny bag. I often have to buy men's sizes and they tend to be heavier fleece.
My Eddie Bauer rain jacket worked better than I expected. It did not promise to be rainproof, but it sure did keep me dry in more than one heavy rain and especially in the sideways wind and rain on Orkney.
My combination of Ahnu Montara boots and knee-high Sockwell compression socks also performed better than expected. They kept my feet warm and dry and were comfortable over all kinds of terrain and through many a shallow puddle.
I'm not a hat person, and the fleece hat I got from Land's End was a little small for my head, but it really helped to keep me warm and to keep the hood up on my rain jacket. So that worked.
All my bottoms worked. I took a pair of lightweight jeans, a pair of Eddie Bauer knit pants and a pair of prAna men's pants. I usually wore the prAnas in the rain because they were so easy to wash and dry. I bought men's because the women's have useless pockets. I love those pants, but for some reason they set off alarms going through security in Seattle and I had to be wanded and patted down. Weird.
My first purchase when I got back to Seattle was a fleece jacket at the Eddie Bauer Outlet. I also hope to get a new zipper for the Patagonia jacket. My next "cold" trip packing strategy is to take one of those, more base layers and fewer other layers. Maybe some day I'll go to a warm place during a dry season and not have to think about layering or staying warm and dry.