This is how I do it.
My 3 season rain jacket is a Montane smock (half zip, no pit zips)
The rain pants are the Montane Featherlite (more like a wind barrier than rain..) or eVent in colder (low 30s) weather.
My base layer is a Merino 140 in summer or 190 spring/autumn.
I wear a synthetic shirt on top of that if cold. When I put the rain jacket on , a layer comes off except for the base layer.
Nylon shorts or longs, not convertibles. I usually have both with me. Shorts for walking , longs at camp.
My wool beanie is in the jacket pocket , just in case.
At lunch I put another layer on, it comes off before I start walking.
The idea is to sweat as little as possible but wool will keep you warm even when wet.
Wool is not wool... there is heavy itchy stuff (not a problem for me...) and there is IceBreaker.
At camp I set up my shelter in a few minutes. Any of my Tarptents set up dry and are ready for me to go in in 2-5 minutes max , and that is when is wet and windy.
Once in I have a full wash (top first and then the rest) change into my "night clothes" and get into the sleeping bag if really cold.
So the trick is to keep moving, set up camp whilst you are still warm and change into something dry as soon as possible.
And have a hot drink as soon as you are dry. (soup or hot chocolate)
Franco