a medium flat rate box is currently 14.35, large, 19.95 according to the USPS website. Smashed in, you can get about 25 yards of fabric into a large flat rate box.
I haven't read the blog, but I know from the Quilt Show show,
https://thequiltshow.com/component/a...qs-legend-2018
she has poured a ton of money and time into making her town a quilt town, and totally fun to visit.