I do all of my backpacking in CO/WY (summer and early Fall) or UT (Spring/Fall). The clothing item that I have struggled with lately is sleeping pants. Under most 3-season conditions, I hike in my light-weight hiking pants and wear a pair of Paradox base layers (bought at Costco) to bed. I often bring two pairs of these base layers so that I can potentially wear one while hiking or around camp if I am cold, but I almost never end up needing them for that purpose.
My dilemma is that sometimes that single pair of base layers is not quite warm enough at night for me. When the temps dip below 30 degrees or so, I have sometimes needed a little more. I have on occasion doubled up my two pairs of base layers, but that makes them very tight and is not the most comfortable solution. When I expect the temps to get to the mid-20s, I have sometimes had to bring a warmer pair of synthetic sweatpants that I own; these are overkill and quite heavy (about a pound or slightly more).
It seems like there are three potential solutions: buy a heavier-weight pair of base layer bottoms, buy a light/mid-weight pair that layers better (not quite as tight) over my current pair, or buy a slightly warmer pair of sleeping pants that I can bring along if the conditions warrant. Does anyone have any recommendations for any of the above, or any alternative solution?
Thanks in advance for any feedback!

