I'm not sure how to word this quite yet so bear with me:
Let's say a group of people want to revert back to an agrarian society, but want to take with them some modern innovations that would be helpful to them in ways historical agrarian societies, like those found in feudal Europe, didn't have the benefit of using. Or maybe there is even a group of time-travelers introducing said concepts to an ancient agrarian culture that they could easily reproduce in their time (whatever helps you get into this idea). What would be good things to take with them or introduce to this society that they could readily reproduce with the available resources?
Let me set some parameters: in this scenario, much of modern technology is left behind. Let's just go ahead and get rid of anything even remotely resembling a computer or a cell-phone. Nothing like that will make the transition. The same goes for cars and most major forms of transportation. Maybe even nothing so advanced as a bicycle. Basically anything after the Industrial Revolution. Anything that can be readily lumped into this pile should be; unless it can't be helped for the sake of argument, I'd like to not resort to using anything like this.
But...say...they were to bring along some of the ideas we've since been able to implement into building cob or rammed-earth houses? Sun ovens or rocket-stoves? Natural below-ground refrigeration or pot fridges? Practical means of rainwater capture? Composting toilets? Biosand water filters? Greenhouses? Things of that nature. I guess you could consider them low-tech innovations, stuff that might be eco-friendly and/or present in helping developing countries have better quality of life without the need of money or advanced technology.
Or, say, just simple and intelligent tweaks and redesigns to existing technology that makes it more useful, but in low-tech ways? Like, smart storage designs to maximize small spaces? Tools that can do more than one thing? Improved weapon design? Or maybe innovations in how we do certain things? Like...what things have we done in the realm of growing crops that could help a culture like this? Or raising livestock? Hunting and gathering in general? Basically anything we've learned in the resulting centuries that would have been useful - and doable - in those times.
I guess I have to ask the question of whether or not some modern-day conveniences could be replicated through almost anachronistic means in this type of society...like, say, running water and a plumbing system of some kind? I know that the Romans had some sort of system approximating this, and I believe other civilizations did too (unless I'm remembering wrong). Would there be other similar ways to replicate or approximate these things? And what would they be?
I'm not sure how much of our modern world, or what facets of it, can be taken advantage of in this context. So I'm throwing a wide net, and hoping people smarter than myself can fill in any blanks. And I would very much like to know how you think a society like this would come to look like and function.