Honestly, I believe the best use for tops like this is to quilt them and use them (or store them as completed quilts). The reason they were in that tote for so many years is that they were not quilted. Nobody knew what to do with them, so they got stuffed away somewhere until they were finally donated to the sale. If you store the tops again, chances are they will end up in another donation sale years down the line, no better off for having been stored and probably worse off. Although you may store them carefully, most people do not know how to properly care for fabrics long-term so they could easily end up in a cardboard box with wood acid eating away at the already fragile fabrics. Quilting these tops will preserve them.
I am very much against washing the tops before they are quilted because it is so risky. With many old fabrics in a top, washing can result in very uneven shrinkage of the fabrics that causes distortion that cannot be ironed out. It can also result in frayed seams. If you absolutely *must* wash a top before quilting, heavily baste the top to a washed sheet before hand washing. This will keep the seams encased, so less chance of fraying, and will provide support to the fabrics so they are less likely to dry distorted. But, in my opinion, it is much better to quilt the tops and bind them before washing. (Retro Clean is another possibility for washing vintage items.)
It is perfectly acceptable to machine quilt hand-sewn quilt tops. It does not destroy their value at all. In my opinion, it actually enhances their value (see Dunster's link). Above all, quilting a top preserves it for the future. The top is much more likely to actually get used or displayed after it has been quilted, and is much less likely to end up yet again in a cardboard box or paper bag at a church sale. If you are not confident with your current quilting skills, I would either practice to acquire the necessary skills or pay someone else to quilt the tops.
If you have the opportunity, you may want to consult a textile conservationist (check with local museums and historical societies). I think they will echo my opinion that these tops would be best preserved by quilting.