I bought a pack of A5 sized sheets of Indian khadi handmade paper and wondered how I would actually handle it when outside. I decided that a little drawing board with some bulldog clips might do. A piece of marine plywood made a light but strong back, but the clips got in the way. I replaced them with a couple of loops of elastic.
That worked, but the knots in the elastic got in the way, so I drilled the boards, ran the elastic through the holes and stapled the ends to the ply. That worked well.
I made a cover out of a sheet of a different, irregular Indian paper, which I painted with several coats of acrylic paint and medium on both sides. This makes it into an almost leather like material. It all slips into a bag, and I spent an afternoon sitting in the garden sketching various bits. The beauty is I can put any type of paper I like into it, so far more versatile than a sketchbook.