The multi-directional scarf pattern says you can make a 4 inch wide scarf with 200yds, 6 inch wide one with 300 yards. I have 100g = 250yds of Mountain Colors Twizzle. Rough interpolation says I could make a 5 inch wide scarf. Of course all is dependent on gauge and density. And nowhere does the pattern say how long it will be.
edit: well I am redfaced. Kathleen pointed out my reading comprehension error. The directions refer to making a four or six FOOT long scarf, not four or six inch wide scarf. I am still off according to her calculations. I ought to have a 5 foot scarf, but will only have half that. Is my fabric really that dense?
Ball band says use US4-6 and I happened to have a US5 needle handy.
Set up part took 7 grams. Assume the end part takes the same amount. That leaves 86 grams for the short-row triangle parts. Triangle took 16 grams. Therefore I can make 4 more triangles before having to decrease for the last bit. That means my finished scarf will only be 30 inches long.
I could/should probably frog this and go up to a size US6 or even US7 needle, for something a bit more drapey, but I think the existing density is also fine. Even if I redo it with larger needles, I am still going to need another hank to make a decent sized scarf.