I find orphan blocks work well as large coverage for crazy quilts I use all my scraps up in crazy quilts so when I cover a large area with an orphan block, it reminds me of something I have done in the past, most likely given away. The edges of the block are then covered by other scraps to make it all blend in.
BTW - I use muslin as a base for my crazy quilts and do a lot of sew and flip, then sew over the edges with crazy blanket stitches from the sewing machine.
tim in san jose