As I move towards lighter backpacking, I'm excited beyond words to finally get rid of my 10-year-old, 4-lb North Face synthetic bag. But given that lightweight sleeping bags are en expensive item, I want to take my time and make the right decision.
So, I would love some input on my thought process.
The first thing to know is that I'm extremely allergic to down, so everything must be synthetic.
The second is that I use a NeoAir Xlite.
I camp in a wide range of temperatures/conditions, from the upper 20s to the 70s, including:
-muggy Northeastern summer nights with lows in the upper 60s/low 70s
-Summers in the High Sierra with lows in the 40s/30s
-Shoulder season trips with lows in the upper 20s
The upper 20s, or perhaps 25 at the extreme, are the lowest temperatures I ever camp in – this would be, say, an October cold snap in the Adirondacks.
So, what combination of bags/quilts (with appropriate layers) would best serve me through this range of temperatures?
I'm thinking about the MLD Spirit 28 quilt for covering the low end of the range. Does this seem like a good call? And how warm could I take it – what would be the warmest temperatures at which I could comfortably use it?
And then, what should I use for the remaining part of the temperature range?
Thanks in advance for any advice!

