If the weather is warm you can forgo the under quilt. My preference is for something under me once temps drop below 72F. I can be good with a simply underquilt protector (which is is kind of like a second hammock in a wind-proof fabric hung under the first. From there, I’ll change the quilts based ambient temps. I try to choose a quilt rated at about 10F below the expected ambient. Obviously, given that I am out year round, I have a collection quilts down to a toasty 0F. When combined with down pants, beanie and jacket I am good into negative numbers.
If your kids have one that is at least eleven feet, it could be a fine. For lounging you can get away with ten footer, but for sleeping the larger is best. In a shorter hammock, your legs extend into the gather at the end and you are vulnerable to something called calf-ridge. It’s a tight section of hammock under your calves that make it really uncomfortable to sleep. Add a ridgeline to the eleven footer and you can be good to go.
I often use just one tree with the Jeep roll bar as the other anchor, but there are more than a few options to replace a tree or even two. Tensa Outdoors is a company that makes a few options that can put you in the middle of nowhere, with no trees.
