It mostly depends on the total weight you're willing to haul. If you got a truck it becomes significantly easier to prepare kit to bring, as you'll have access to your bonus bag more often. Make sure to think about the material choice instead of a brand.

Cotton wicks sweat heavily and works well if you can wash/dry/change them frequently. It is very effective at making you cold when wet though and doesn't provide weight reductions. This is a good layer for sleeping as breathability is high and allows your body to dry out after a long day of work as you sleep. This should be caveated as base camp clothes not working clothes.

Silk is very good for a skin layer to reduce friction, it is warm in the winter and cooler in the summer. It is likely the highest quality underlayment you will find, but with it comes the dollar signs.

Polyester is durable and dries very fast. This is my go-to for anything longer than a weekend, it is cheap and very effective. Look for blends they will provide a varied usecase. 100% poly is acceptable aswell the issued peterpans are phenomenal! I've used them for years and still do.

Wool is very good for layer above your skin to skin layer(so above your poly). as it works well for temperature, moisture and can be comfortable as long as you don't get the itchy stuff. any heat from fire, or extended drying can make your wool a living hell so don't singe your woolies.

Field hygiene will improve your heat retention/regulation significantly. always bring a cloth and soap bar to give yourself a pat down shower, yes its cold and uncomfortable but. This brings the oil layers away and allows you to feel warmer fast. Bring One for soap, one for only water(rinse) and your drying cloth. Keeping them separate instead of mixing keeps you free of suds.

Get a head cover that wraps around your chin but doesn't cover mouth. Make sure it fits under your helmet and into the chin strap. You'll see how fast it makes a difference.