Are you going to need a nap mat for the upcoming school year? I thought I would share what I ended up doing last year when my daughter needed one. Instead of buying an expensive one or ordering a fancy custom-made one, I thought I would try to throw one together cheaply and easily. I am by no means a seamstress, but I can sew a straight line with my machine. And that's all you need to be able to do for this project. And honestly, you could probably do it without a sewing machine!
I realized that I had a roll of 19" x 36" foam that I had bought from Joann's for another project that never happened. I thought about sewing a cover for it but while I was at Kmart one day I saw that the zip on body pillow covers were the same width and had extra length that would allow me to stuff a travel-size pillow in the top. My girly girl really wanted a frozen themed mat, so I used some fleece that I already had to make a pillow cover and attached it with my machine to the top of the body pillow cover. That left some extra fabric that had to be cut off, but like I said, you don't have to make the pillow cover, you could just stuff the pillow inside the body pillow cover. And, voila! It rolls up easily, and another bonus is that the body pillow cover has a zipper on it so you can easily take it off and throw it in the washing machine.
approximately 19 x 36" foam about 2 inches thick.
Body pillow cover (found mine at Kmart)
Travel sized pillow (found mine at Kmart)
Themed fabric if you want to make a cute pillow cover (not necessary)