For scuba diving I use Smart Wool as a thin base layer. I have polar fleece drysuit undergarments that I wear on top of them. I love smart wool and even with my chronic dry,sensitive skin it rarely causes me to itch.
I also have some Walmart polar fleece that I love,especially for mild-medium cold weather.
Have you considered some insulated breeches? I have some from Ariats in black that are great for day to day riding and even nice enough that I wear them to work at times. May be hard to find nice winter white breeches in white,though.
I have a pair of the Kerrits capri length base layer and I really like them. donât add bulk under boots but keep my thighs warm. This is them, apparently discontinued, mine are black.
http://www.thetackyhorse.com/index.php?main_page=product_info&products_id=2569
headed to Walmart for Cuddl Duds before PTF Advanced weekend for sure! Now, any suggestions for gloves and socks? My fingers and toes really suffer 
Another vote for Techwick- I have the heavy ones, and they fit under my breeches and my boots still fit. They are good long underwear in general, but I have been happy with their ability to keep me warm riding.
I have taken them on all my Irish foxhunting trips and they keep me warm and dry very fast. Although on this latest trip I was introduced to⊠WATERPROOF Fleecelined breeches that look good enough for the show ring! âeveryoneâ was wearing them.
They are made by Horseware but donât seem to be available in the states. 
I found a tack shop and bought a pair and they are really nice.
These: https://www.dealsplus.com/Women_deals/p_6-pairs-fleece-lined-seamless-leggings Iâm not kidding when i say I ordered 18 pairs! Super cheap, slick enough I can pull breeches up over. Love these things!!! The $29 price tag is for 6 pair.
Smartwool Knee Hi socks. Not a thin as boot socks, but not too bulky that I canât get my tall boots on.
Word of advice: Cuddleduds first, then wool socks pulled up to keep Cuddleduds from riding up, then breeches to keep socks from riding down. Same thing on top, base layer top, tucked into Cuddleduds, polo shirt or other top, tucked into your breeches (but in front of your Cuddleduds). Alternating helps keeps everything in placeâŠ
[QUOTE=RunForIt;8529753]
headed to Walmart for Cuddl Duds before PTF Advanced weekend for sure! Now, any suggestions for gloves and socks? My fingers and toes really suffer :)[/QUOTE]
Sock liners are great and help wick moisture away from the skin. I typically wear sock liners and thin wool socks. Layers that are too thick/get compressed by your boot are a recipe for colder feet IMO.
Foot/toe warmers really help. I forgot to put my socks on over my liners yesterday and I was fine with added toe warmers (outdoor temps of around 18°; indoor was warmer though). I sometimes use hand warmers. Sometimes I stuff them in my gloves, sometimes I put them in my pockets depending on how cold it is.
The best base layerâŠum, every mile you head south for the winter.
[QUOTE=snoopy;8530971]
The best base layerâŠum, every mile you head south for the winter.[/QUOTE]
Ha! I am in the South and itâs freezingâŠwill be in 60s mid-week - waiting it out <3
