Thanks for all these suggestions. Most of the fraying seams are along the sashing, between the blocks. I do like the idea of rick rack between them, but I think I'll ask her first. It's been really "loved" over the years, especially during her toddler years and all through her fort-building years. She's now at the age where she can take care of her bedding, though the occasional fort is still erected during sleepovers, lol.