Convert / Mod adult bag for kids.

Maybe make a french seam

Sew together on the outside a little longer than you want

Cut off the excess leaving about 1/4 inch of raw edge

fold it inside out and sew, hiding the raw edge.

Jerry- exactly my thought, a french seam below the end of the zipper (it’s a 3/4 length zipper) to reduce the length, and then something similar along the length of the bag to reduce the girth (though I want to see what the baffle is like before attempting…it appears there is one long side baffle that may be easier to just either remove or “pinch” together and leave in).

I had actually bought a Short Western Mountaineering Megalite someone put on craigslist for $200 this winter, but I haven’t had the heart to cut a WM bag ;) I – feel a lot better performing surgery on an REI bag!

Something I think worth considering is using a full size (and lightweight) summer/3-season quilt and doubling it over. Not sure how tall your children are.

We took our daughter for an overnighter in the Tetons last summer. I took a one of those double black diamond down quilts (costco type) and had previously turned it into a topquilt based on a Serac blog post. For the trip, I simply tucked it inside of itself (basically doubling it over) and she slept in that. She wore a $20 fleece suit (Columbia? idk) too. Got down to mid to high 30s and she was warm. She was 2.5 at the time, and I couldn’t bring myself to pay $160 for one of those Patagonia down suits.

But in your case with the REI bags, I would totally cut from the bottom. A little pricey, but sweet idea! Probably very toasty, and they wouldn’t need a thick base layer. Were you trying to get two bags out of the 1 REI bag? That actually might work… use the bottom (smaller) half for your 3 year old, and the top (wider) half for your 5 year old, provided the lengths work out. If you wanted to do that, maybe try for a long bag?