@jplopez Suggest Smartwool 250 merino wool base layer or REI merino wool base layer unless you have a wool allergy. These are mid weight so maybe not enough for the arctic but I think warm enough for what you are looking for...depending on your sleep system of course.
A fleece jacket or hoody is best for active use. I prefer zipped rather than a pullover even if it is under an outer jacket. For evenings you are probably going to want to add a down puffy of some sort.