NEMO - Tempo Women's Synthetic Sleeping Bag (35F, Long)

Isn't a 3 lb sleeping only "ludicrously heavy" if you're an ultralight backpacker? I have a Nemo Tempo that's 3 lbs and I'm fine with it.

Yes but I haven't really put it to the test yet. I've only had it for less than a year and haven't been below about 40° yet.

Depending on your specific needs for temps, weight, and filling I'd recommend, Nemo's Rift, Forte, or Tempo bags. They have a "spoon" shape (extra space around knees and elbows and tapers around the waist and feet) rather than mummy shape. They're designed to feel less restrictive and I've found them to be so. Of course the bag will take up a bit more space than a mummy bag, but it's better than a regular rectangle bag. I have the Tempo and I think it's good for regular backpackers and I really like it. They're common at REI too so you may be able to try it out.

I just got the Trekology UL R7 sleeping pad for my husband and I. Only slept on it one night but it was comfy. I’m a side sleeper. Trying them again Easter weekend so we’ll see. We got the Nemo Tempo bags. For my kids (about the same age as yours), we got the Big Agnes Divide because it fits in a sleeve for their sleeping bags (also Big Agnes) so they don’t roll onto the ground. We did pay more than some other stuff but we went fairly lightweight and compressable in case we try backpacking too.

I just got the Trekology UL R7 sleeping pad for my husband and I. Only slept on it one night but it was comfy. I’m a side sleeper. Trying them again Easter weekend so we’ll see. We got the Nemo Tempo bags. For my kids (about the same age as yours), we got the Big Agnes Divide pad because it fits in a sleeve for their sleeping bags (also Big Agnes) so the kids don’t roll onto the ground. We did pay more than some other stuff but we went fairly lightweight and compressable in case we try backpacking too.

For clarity - The Riff (and Disco) are down. While the Forte and Tempo are synthetic. Their spoon/peanut shape is definitely very popular with side sleepers, or people who sleep angular or toss and turn. Much more forgiving than a regular mummy, without the draft issues of a quilt. Recommend people getting into quilts, to buy a wide one. This will help mitigate drafts. You mention REI, all of their sleeping bags now come in "wide" versions. Still a mummy for the most part, but about 5" wider than a regular mummy. Their Magma is an excellent bag, as is their Magma quilt, but it's only rated to 30 degrees.

Nemo bags zip together, or at least some of them. I have the tempo and it'll zip with the opposite genders bag.

Mummy can be a bit or very claustrophobic. Depends on a person. There is a great design by Nemo, they have spoon shape bags where you can actually bend your legs. They are for side or stomach sleepers.

Quilts, semi rectangular bags (Sea to Summit Trek and Ascent Down) or the Big Agnes Sidewinder series are what you want. The Nemo Spoon series of down bags are also quite roomy. I sleep on my side. I use Hammock Gear Econ Borrows most of the time and I have a Marmot Col -20F bag for anything 20F and below.

Which 2 in 1 are you referring to? The ones that come to mind would exceed your budget, but examples help.  What temperature are you expecting at night?  Mainly, I would suggest finding an insulated sleeping pad with a stated R-value. Depending on how cold it will be, the R-value changes (higher R for colder temperatures). For sleeping bag, add at least 10°C, so for example, if you expect overnight temperatures around 5°C, find a bag rated for -5°C.  I have a Nemo Quasar insulated pad in the double width (I move a lot), and a Nemo sleeping bag (in their "spoon" style because I can't sleep in a mummy style bag). 

If you want something in between, look at Nemo spoon-shaped sleeping bags.

BLUF: Test fit at a store or use the 30 day return policy. Only you can determine what length you need as there are multiple factors that go into that. Cost is based off several things and comfort isn’t usually one of them. A few things. For determining length: Most camping stores or stores that sell sleeping bags will let you try them on at the store, plus there is usually a 30 day return window. I’ve noticed a difference in actual bag length both from the same brand and definitely between brands so doing a test fit is always beneficial. Finally, how do you sleep? Do you keep your feet at a 90* angle from your legs like you are when standing and measuring your height? Do you relax them or point them away from your head (some side and most stomach sleepers)? Do you put your “pillow” in the hood of the sleeping bag or leave it outside? Do you put your clothes in the bag with you to keep them warm for the next day? All of these things will determine what the right length of bag for you is while remembering that large unfilled space will require you to heat it or fill it. Bag temp should be based off of night time temperatures. Yes, you can use a colder rated bag when it’s warmer, but people often can’t figure out why they are cold in a 10-15* bag when it’s only in the mid 30s and think they need a 0* bag. Price could be due to better materials, insulation (lots of different qualities between the various “synthetic” insulations, type of down and it’s fill count), “compressibility”, brand, and quality of product. Finally, comfort is entirely subjective. Lighter is definitely better when you have to carry the sleeping bag; however, lighter may mean it’s a tighter mummy fit which may make you more comfortable or may make you less comfortable. As a side sleeper/rotator, while I could sleep in a mummy bag, once I tried the NEMO spoon shaped bags I started sleeping so much better and will now only rock a mummy when I’m really worried about weight or when the temps are in the low teens and below. Also, how noisy is the sleeping bag? How noisy is your sleeping pad and bag? And how does the sleeping bag slide on your pad? Some of the fabrics over the years have not only been very noisy, but also very slippery and both of those can cause issues. Once while on a week long backpacking trip, I was ready to kill my hiking buddy because his new sleeping pad was so F***ing loud that anytime he moved during the night it was like someone getting into a fight with a bag of chips and I would wake up. He also had the problem of the two fabrics being extremely slick and so if we were on anything but perfect level ground he was sliding downhill. Needless to say he never used that very nice and very expensive sleeping pad again.