This little loom is 8" wide x approximately 14" high (the nuts on the threaded rods at the sides can be screwed together more or less to make it slightly shorter or longer). I usually place the loom between two pieces of foam core board and stick it in a bag for traveling. I've found that a bungee cord works well to hold the sandwich of foam core/loom together.
The warp on the loom this time around is a hemp thread that I bought at Southeast Fiber Forum from Lunatic Fringe. It's sett at 10 epi and I'm using two pieces of 5-strand embroidery floss as the weft. The piece is about 4" wide and will be around 6 or 7" high. Because the warp is quite short the pick shed is more challenging to make and as I get nearer the top I'll probably use a weaving needle for that shed. I may also change the size of the open shed holder--right now I'm using a thick pencil for that, as you can see.
So my traveling studio consists of a book bag into which I put a set of small scissors, a small bobbin or two, a package of assorted tapestry needles, a couple of zip lock bags with assorted wefts, and the loom. I can sling it all over my shoulder and lug it along just fine. In the car the bag of stuff sits by my feet and I prop the loom in my lap to weave. Oh... a recent discovery... a Subway napkin hanging from the sun visor in the car gives just that extra blocking of the low position of the sun when the car is headed southwest in the late afternoon!