
NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.

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The older I get the thicker the sleeping pad... Where I live, I need 3 distinct sleeping bags - warm weather (Big Agnes), shoulder seasons/early winter (Nemo), and extreme winter (Big Agnes - takes up the whole backpack!) I have an REI half dome tent - big enough for weekend camping, small enough that I could backpack with it if I'm not using a hammock. I also have several Coleman Sun Domes as lenders, and my boys each have a Kelty when they don't hammock. For front country camping, a nice comfy camp chair is worth its weight... consider a lightweight backpacking chair as an addition or alternative. You can enjoy a lightweight camping chair in camp, but hard to take an XXL rocking camp chair backpacking... Consider hammocking, too, but that's a whole additional rabbit hole to travel down.
It might depend on how you're built, but I can get my leg up like that inside my Nemo bag. I have short legs, though.
I really wanted to love the Nemo, but if OP is a smaller person, Id warn they have too much dead space.
Nemo. Best sleeping bag I have used. On my second one.
I'm a side/stomach sleeper and love my Nemo sleeping bag. I have a synthetic one and it's quite bulky, but the down ones would compress better.
Ok so it’s important to know that the degree rating on bags is the survival rating. This is the “you probably won’t die of hypothermia, but you’re not gonna have a good time” rating. Rule of thumb is to add 10-15 degrees F to any bag rating for the comfort rating. Always err on the side of caution with colder temps. If you get warm, you just open the bag. Some bags even have vents (my Nemo bags do). There are some tricks to stay warm with a bag, but for high 20’s, get at least a 15 degree rated bag. And have your son bring some good under layers to sleep in as a caution.

NEMO
Disco 15 Series
Spacious for side sleepers; bulky, temp rating optimistic.
Hammock Gear
Classic Burrow 20°F
Budget king; very warm but heavier than ultralight.

NEMO
Disco 30
Spoon shape for side sleepers; prone to zipper issues.

Western Mountaineering
VersaLite
Durable, very warm; premium price, too hot in summer.

Katabatic Gear
Alsek 22°F Quilt
Versatile 3-season quilt; secure pad attachment, high price.

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Kelty - Tru.Comfort Doublewide 20
Ranked #1
Enlightened Equipment - Revelation APEX

Ranked #1
NEMO - Disco 15 Series

Ranked #1
Feathered Friends - Egret UL 20/30

Ranked #1
NEMO - Disco 15 Series