It washes and dries fine. I haven't had a problem with it.

I made lot of bibs and changing pads for my grand using it. I've seen lot of the diaper covers made from it too. I used Riley Blake.

What are sleeping bags made of? I always took one for outside games when cold and rainy and put my feet in, pulled up to neck and I was nice and toasty!

After living in Bremerton, WA and freezing all the first winter, I learned the value of a fleece coat. Fleece does not absorb water, wind doesn't go through it, and stays nice and toasty through the day outdoors. If I were making any kind of blanket to stay dry and warm, I would use fleece. Just remember to shake the water out of it before bringing it into the house. They do not absorb, but water does stand on it, so shake it off. If you make a custom size fleece blanket, with strategically placed snaps, and a built-in hood, you could watch a triple header staying nicely warm, and dry while doing it.

I use a vinyl table cloth to lay on the ground with the flannel side up and then lay a blanket over it. Years ago I also had the vinyl pad from a play pen that had given up the ghost and used that until it too wore out. That was really good because it was lightly padded and stayed in place better than the table cloth. You could put some grommets in the corners of a table cloth and stake it down to keep it in place and then lay the quilt over that.

I believe there is a product that is called Gortex that is waterproof.

I used some of the PUL fabric at JoAnns for a travel dirty clothes bag. It is waterproof, has a nice hand and I don't think wind would get thru either. It mostly comes in kiddy type patterns as it was made for bibs and diaper covers. I found a black and white zigzag that is easy to see in my suitcase! It would work well on one side and you could sit on it (with the PUL down) if the seats are wet. It is not located in the fabric area but I found it near the trims and elastic. It comes on a roll or bolt (I forget which)