If you do hand work of any kind, just find the appropriate sized ziplock bags to put the project in and carry it along.
I've almost finished (finally) a queen/king hand pieced Around the World that has been a WIP for about 3 years now (several other projects finished in between). Each color 2-1/2" square has it's own sandwich bag (placed in order of use on the bookring) and the final bag on the bookring has spool of thread, package of needles, seam ripper, small scissors.
I started the design by stitching the first round of 2-1/2" squares around the center square, then stair-stepping the following rounds color by color. I'm to the point that one corner is completed and the other three just need the last 6 or 7 rows. Had to cut another strip of squares in a couple of colors as I had not cut enough of some of them.