Wow -- that is a mighty nice quilt! I agree with the recommendation on the pack liner. I use a large Ultra Sil dry bag (25 or 30 liter -- would need to check) from Sea to Summit for my clothes and then a few smaller ones for sleeping bag, shave kit, etc. For less delicate items (Crocs, dirty laundry), I occasionally use Zip-loc bags with the air squeezed out.
For that epic quilt, I humbly suggest grabbing an Ultra Sil dry bag dedicated to just the quilt. Since it's synthetic insulation in the quilt, I suspect that pressing the air out before sealing up the bag won't affect the amount of loft (I have a down bag that I don't like to store in a compression sack for long because of fear of loss of loft / insulative ability).
Would love to hear a report back on what you think of the quilt for use on the Camino. I'm curious about the sections that wrap under the body -- e.g., are there any seams that rub, is there excessive fill material, etc. Good luck!