I sure hope your surgery goes well, and that your recovery time is swift. Let us know.
When we go on longish car trips, I use felt and zip lock bags. I cut the felt into 4" squares: one for needles, one for straight pins, one for my scissors, one for safety pins--for "just in case." I include 2 or 3 spools of thread--depending on how much I think I'll get done--one spool is usually enough, but I'm ever hopeful; a fabric glue stick, a needle threader or two, a seam ripper, thread conditioner, needle-nose pliers (for hand quilting mostly, but also for when my hand is tired), and a thimble. I use a small pony-tail holder to wrap one square of felt around the tip of my scissors. Haven't gotten around to making a fancy holder yet. I put the to-be-sewn pieces in one bag, the finished pieces in another, the tools in another and stick them all in a gallon size zip lock. I like the zip lock because I can readily see everything and don't have to dig around to find stuff. I try to keep it simple and take the bare necessities.
As for the size of the Hexies, depends on the feel you want, maybe smaller for traditional and larger for a more modern feel (and maybe a faster quilt?).