I have thought about this at some length and being an avid seamstress it would be distressing to not have fabric to sew new or repair old clothing. I have bolts of muslin,denim,canvas stored in Rubbermaid tubs. Plus a huge stash of quilting fabrics. Also sewing thread,needles for hand and machine sewing, extra bobbins for my old treadle machine if I need to dig it out,zippers and a big button box. If new clothes aren’t available keeping the old ones patched will be very important. Some good places to get sewing supplies are www.homesew.com  or www.newarkdress.com . For bolts of fabrics try www.hancocks-Paducah.com . These are all reliable companies I recommend. Often I find such items at garage sales for pennies on the dollar.
On the same theme it would be wise to store sturdy work clothes, extra boots, shoes, socks, underwear, and work gloves. it is hard to work with inadequate clothing. I’m always on the look out for good bargains and I’m never averse to hand-me-downs. I have a collection of basic sewing patterns for shirts/pants/jumpers/pajamas for adults and kids. A lot of the patterns today are multi-sizes in the same package which is helpful. Learning to knit/crochet will enable you to have plenty of warm hats, mittens, sweaters, and socks. It is a relaxing hobby. All my kids can knit. Yes, even the boys! Just as they can cook, garden, can, sew by hand or machine. Yes,patch their own pants! – Dee
I live near a large Amish Colony and I was visiting their local General Store. Back in the Fabric Department was a treadle cabinet with a modern sewing machine mounted on it. They had removed the motor and had a stout belt attached to the drive wheel on the right side going down to the treadle drive cam. I thought that this was the marriage of the best of both of our worlds. I inquired as to how well it worked and the lady store owner said she made all of her family’s clothes on it. So I guess that means it works well. – Carl in Wisconsin
You wrote: “The Memsahib and I do have some experience with treadle sewing machines. In addition to a spare drive belt and plenty of needles, the most critical spare part for a treadle sewing machine is its shuttle (a.k.a. bobbin holder). They do eventually wear out. Thankfully, these are fairly easy to find for the Singer brand, but replacement shuttles for New Home and some of the other less popular brand of sewing machines can be quite hard to find. One great resource that we found for treadle sewing machine information and parts is Treadle On .”
I went to Treadle On and an extensive search on eBay and other sites and could not find anyone selling shuttles for treadle sewing machines. In particular I have a 1923 Singer Treadle Sewing Machine [Model] 66. Where would you suggest I go to find it?
Thank you. I love your site and read it every day. I have recommended it to about six other people. – Nancy
JWR Replies: There are currently two Singer shuttles up for auction at eBay. Just be sure to use loosely-worded search phrases like “Singer treadle part” or even just “Singer part” since some people use incorrect terminology or have typographical errors in their item descriptions. People call shuttles all sorts of things. I’ve found them in the past with auction titles like “Treadle Sewing Bullet”, “Singer Bobben [sic] Holding Part” and “Singer Thread Holder” Good luck bidding!